It
is the study of the location and distribution of living things and earth
features among which they live.
Geographers
study where people, animals and plants live and their relationships with
rivers, deserts and other earth features.
They
examine where earth features are located, how they came to be there and why
their location is important.
To
many people geography means different things and a geographer’s work in many
cases is misunderstood by the general public.
People
see geographers as those who poses knowledge of far distant places or
possessing close to encyclopedic knowledge of places and who are able to give
you answers (many names and fact files) of different places at a click of a
finger tip.
To
others geographers are like moving atlases, they are genius on TV quizzes about
people and places but have no other value beyond this knowledge.
Yet
a third group associate geography with map and map making, simulating charts
and globes without realizing that various global challenges and changes that
are taking place throughout the world.
Geographers
have a lot of work to do that contribute to the national development, We have
to emphasize that modern geography doesn’t merely describe places or regions
but goes on to analyse the various phenomenon in these places.
In
broad terms geographers deals with location, spatial relations, Regional
characteristics and the forces that change the earth.
GEOGRAPHERS
-
Analyse the physical landscape and
examine the relationships between places and offer explanations on the various
observed and how these affects distribution of man and how is many economic and
social activities.
-
Explores the relationship between the
earth and its people through the study of place, space and environment- asking
questions of where, what and also why and how?
-
Investigate the interrelationship
between people and their physical environment (facts percell have no meaning it
is information which is not the same as knowledge. They only have meaning if
they are related or organised into some sort of system). And appreciate the
complex interactions of people with their environment.
-
Examine regional differences, patterns
and interrelationships and attempt to account for them (the regional framework
and analysis of specific regions) this is part of the study of area differences.
-
Emphasize on spatial pattern and
relationship so as to get a better understanding of both the physical and human
world. In whatever data she/he studied the geographer looks for spatial form
and spatial relations- pattern of distribution and interactions.
-
Studies the environment from the
holistic perspective (both its physical and human dimension) and thus addresses
the natural resources upon which all life depends, their impacts on human
activities and the wider social economic, political and cultural consequence of
the interrelationship between the two.
This
was dominated by Ancient Greeks especially Plato who used the deductive method
and Aristotle who used the inductive method. Their main concern was to answer
the question what is where? They gave descriptions of places and different
phenomena. They did not answer the questions: Why are the phenomena where they
are located? And why do they behave that way?
Why
are the phenomena located where they are? They believed that the environment
dictates the kind of activities to be done at a certain place.
This
paradigm developed much in Europe.
It
failed to answer the question; what is the influence of man in the environment.
The
environment provides different options or alternatives to which you can put it;
human beings make decision on what alternatives to take.
The environment does not dictate decision
making.
It
failed to realise the interrelations between human beings and the environment
They
believed that the phenomena behave as they are behaving due to regional
differences.
Climate,
soils and vegetation were taken as some of the criteria to define the region.
This
paradigm divided the world into natural regions which are unique.
This
uniqueness was rejected by some geographers: they claimed that it was difficult
to demarcate regions which are permanently unique; it did not come with a clear
testable way of assessing human impacts on the environment.
Regionalism
changed into spatial analysis of geographic phenomena.
It
started in the US. It is an attempt to make Geography systematic science which
can make laws and theories. It aimed at making geography scientific by using
scientific methods.
In
previous paradigms there were no laws and theories. The approaches were descriptive
The
scientific approach uses the philosophy of mathematics and statistics to arrive
at conclusions
Regionalism
in its various forms was the dominant geographical paradigm used in teaching
and research in geography after replacing the environmental determinism and
possibilism paradigm in 1930s and 1940s. However many geographers blamed it for
the low self esteem of the discipline in the 1950s and argued that it did not
afford the necessary balance between regional and systematic studies. They also
argued that uniqueness of places that regionalism emphasized tended to ignore
the search for generalization that would offer better explanations and allow
for wider application and insight into geographical phenomenon. They believed
that their approach and adoption of quantification by the wider geographical
community would make geography to be more respected and recognised academically
as capable of contributing worthy knowledge to solve the many problems that the
society was facing in the 1960s as opposed to its then status that they
considered to be intellectually weak, being held in low esteem by other
discipline and being descriptive and lacking in theory. The main difference with the regional school
was the greater faith geographers had in their ability to produce laws and work
within the accepted scientific methods that were increasingly defining social
science research.
Any
research is the logical process, i.e. appears logically. It possesses the
following characteristics:
i.
The research begins with the question in
the mind of the researcher. This question should be intelligently asked in the
presence of the phenomena that the researcher has observed and which disturbs
him. The question may involve unresolved and confusing situation around you.
ii.
Research requires a plan: It is not
aimless, undirected activity. It requires a definite plan direction and design.
To
ensure a good plan there should be:
·
A clear statement of the problem
·
Development of hypothesis
·
Data gathering and interpreting design
·
Test of hypothesis and an arrival at
factually based conclusion
iii.
A research requires a clear statement of
the problem: Here unanswered questions that the researcher finds indigenous to
the research situation must be put clear at the very beginning of the research.
Before we begin we need to understand the problem. We look at it objectively.
iv.
Any research deals with the main problem
through sub problems. Most researchable problems have within them other problem
areas of lesser breadth and importance
v.
Research seeks direction through
appropriate hypothesis or research questions, having set the research problem
and the sub problems. The sub problems are then viewed through logical
constructs. “A hypothesis is a logical
supposition, a reasonable guess, an educated assumption which may give
direction to thinking with respect to the problem and thus aid in solving it.
vi.
Research deals with facts and meanings:
Having isolated the problem, subdivided it into appropriate sub problems, and
formulated hypothesis or research questions which will suggest the direction in
which the facts may lie, the next step is to collect whatever facts which may
seem to be pertinent to the problem and to organize them into meaningful
aggregates capable of being interpreted
vii.
Research is circular
Science
is an objective activity undertaken within very strict rules, and it involves
the continuous excitement of search for new discoveries under a certain set of
values universally subscribed to within academics.
The main tenets/pillars of academic
research
Originality
Original
work intends to discover new knowledge, addition of knowledge on existing
knowledge, comparing of things and it is not duplicate.
Communality
Sharing
of information with the public is expected after work. It can be done I
publication, seminar, workshop or forum.
Disinterestedness
Objectivity
not being guided by your opinions; use of scientific procedures
Universalism
if a research is done in one area it should bring the same results on other
areas with similar characteristics
2.4.1 Problem identification: A problem is anything
that requires some explanation. A problem must be clearly defined. A problem
can cover anything, e.g. population growth and plan, population movement,
Dynamics of human settlements, Urbanization process, economic growth, etc.
2.4.2 Gathering available information or data: You need to read
widely what has been written about that particular problem. Relevant
information that is available must be collected. This data is available in
statistical publications, books, journals, News media, census reports,
Historical documents, research documents, etc
2.4.3 Primary data or original data collection: Secondary data may not
suffice the problem. The research has to collect original data. This is the
data one collects from the field. A research advantageously collects from the
field data that is relevant to the problem using different data collection
techniques.
2.4.4 Classification or summarization of data: Data
or facts that are collected must be organized or grouped to suit the study. The
process is known as data classification. Items with similar characteristics are
arranged in classes. Summarization is done so as to reduce bulkiness. Summarization
is done through techniques that give use of numerical descriptive values which
come up with measures of central tendency, Deviation
2.4.5 Data analysis:
Data is analysed so as to come up with explanations and conclusions. You derive
meanings from the data through analysis and interpretation
2.4.6 Data presentation:
The summarised data is presented using tables, values graphs, charts, diagrams,
maps. Qualitative and quantitative measures help to understand the relationship
between values.
A
point that needs to be stressed here is that research is hardly conclusive.
This is because in exploring one area a researcher comes up with one or several
problems that need resolving.
Research
needs no to be seen as one time act static and an end itself. Genuine research
is dynamic. It creates more problems than it solves. In deed reading through a
number of research report you will notice that researchers point to areas of
further research a suggestion that their studies uncovered many issues that need
to be considered by themselves or other researchers. Such is the nature of the discovery of truth.
In this way therefore research is a circular process.
What
is data? Data is the body of
information mostly presented in numerical form (sometimes found in a textual
form)
Before
any statistical analysis can take place data must be collected (Raw data)
·
Data are precise numerical facts:
·
The information they give is
quantitative rather than qualitative.
·
They can therefore be manipulated
statistically,
·
They can be stored in digital forms e.g.
tapes, CD-ROMs etc
·
Data is usually collected for a definite
purpose.
·
Collection of data must therefore take
time,
·
Involve measurements and surveys of
various types.
·
The justification to collect data is to
test a theory or hypothesis
·
The quality of data depends on
reliability and accuracy of a researcher.
·
Care must be taken during data
collection.
·
To maintain the quality of data certain
things must be avoided in data collection: These include: Making mistakes,
Subjectivity, biasness.
·
The collection of data and methods/ techniques
must suit the purpose of research.
·
Data should be valid and reliable. To have
good data you need to be objective rather than subjective.
Davis
(1974) Insisted that the common feature of geographical data is the fact that
it is spatially distributed over time and space. Geographical data have time
and space.
The
values of geographical data have been related to points, areas and lines. For
instance when dealing with population data, the points can be used to represent
the population density.
Geographical
data can take various forms including:
Altitude:
Heights of landscapes, always presented in Metres. This data can be presented
in form of contours.
Rainfall:
A rain gauge is used to get the amount of rainfall in mm. This data can be
presented in the form of isohyets.
Temperature:
Presented in the form of isolines
Population
statistics: Presented in the form of dots
Traffic
flows: Presented in flow line map forms\
The
aim of collecting all these data is to solve geographical problems
Geographical
data can be;
Individual
data provides precise and specific values of every item
in the sample population. This data is very informative, thus very difficult to
tabulate if the data set is too large. It is suitable if the population is
small.
Grouped
data: This represents the grouped/class values
information. The groups are formed arbitrary e.g. age groups. It is convenient
when large numbers are involved in research
Discrete
data: Data presented in whole numbers due to their
nature e.g. Human beings, cars, etc
Continuous
data: Presented in the value over a given range,
temperature, rainfall, height, etc. It is the type of data where you can get
fractions.
Primary and secondary data:
Primary
data: Information acquired directly from the field
Secondary
data: The kind of information obtained from other
people’s findings
-They
help to facilitate description:
ü Summarising
or converting information into mathematical language
ü enables
one to easily understand and interpret the phenomena. It enables easy
comparison of results.
ü Enables
the understanding of the phenomena.
ü It
enables the reduction of massiveness of data.
ü It is good for the manageability of
information.
ü Enables the researcher to quantify data by
giving numbers to data in a way that data becomes objective and look
scientific.
-Statistical
methods enable facilitation of induction/ making of inferences. Generally the
whole information is very difficult is very difficult to study.
-Statistical
methods make it easier to generalise information about population from the
sample. It enables to make inferences about the whole population leading to
objective decisions.
-Statistical
methods enable researchers to test the significance of the results.
-They
test the relationships between sample data whether they are significant or a
result of chance.
-Statistical
methods allow the making of predictions: Predicting what may happen in future.
This requires understanding of past events. The past events on the context of
geography are spatial. They may be past while existing. With this knowledge
prediction of the future is possible
Limited
time: the amount of time available to a researcher
determines the research design, the type of data to be collected, analysis
strategy, etc
Reliability
and accuracy. This mostly concerned with stability
and consistency. If not acquired the data collected can not be reliable.
Lack
of reliability and accuracy leads to biases and
invalidity. Highly unreliable measures can not be valid.
-Inability
to reach certain populations (inaccessibility). Certain populations may
not be accessible e.g. due to remoteness (topography)
-Data
disaggregation
-Introduction
of errors
Global
warming, Loose of biodiversity, Pollution &Exposition of finite resources.
To
solve this problem the developing countries has to exact pressure on natural
resources.
Spatial
diffusion have been fostered by ICT revolution in the way world have been
unified in terms of corporate and finance for Example agricultural information
for multilateral corporations. Change
from agriculture to industry which leads to change from village to urban.
·
From religion racism
·
Cultural conflict and conflict over natural resources
e.g. environmental degradation such as
deforestation and overstocking.
Research
involves carrying out a diligent inquiry or critical examination of a given
phenomenon such as a critical analysis of existing conclusion or theories visa
vies newly discovered facts.
The
purpose for any research include all or some of the following:
i.
To discover new knowledge ie new ideas
or new facts
ii.
To identify and describe new phenomenon
iii.
To make predictions and make estimation
of a phenomenon
iv.
Enable control
Offer explanation of a phenomenon based upon described characteristics ( give a critical reasons why something is
happening) for example there is a very high dropout rate why
Why there is low crop production or why road accident or impacts of
rainfall variability or what can maintain price of a particular crop in the
market.
v.
Enable theory development or
confirmation, validation of existing theories (basic research) or develop new
ideas that strengthen a theory.
vi.
Solve a specific problem i.e. in
agriculture genetically modified food (GMF)
Research
is classified according to
i. Data collection
ii. Analysis
iii. Purpose
·
Applied research
·
Basic research
·
Action research
·
Evaluation research
·
Qualitative research
·
Quantitative research
·
Survey research
·
Historical research
·
Descriptive research
·
Case study research
·
Experimental research
·
From existing literature ie. systematic reading of previous research work and
or published books
·
Existing theories
·
Opinion/ insights from experts/ peers
·
Media reports (things which are frequently reported ie news papers, radios, TV
·
Personal experience/ practical issue ( the work related experiences ie
technological change and experience.
·
New policy
i. Survey
ii. Case study
iii. Experimental
strategy
iv. Ethnography
It
is characterized by one common thing wide and inclusive coverage, Bringing
things up to date. Getting snapshot of how things are at a specific time during
the survey.
It
is an in-depth study of a particular situation or event
Manipulation
of circumstances, identifying significant factors, introducing or excluding
some factors from the situation, observing effects (manipulation and control)
Here
is not an interview to people for little time but one need to spend a lot of
time with people whose culture you want to understand.
Example
why people prefers this? Why they live there and how they passive life.
There
is no one right strategy or correct strategy in doing a research.
There
is no best strategy but the one which can help to solve a problem is the best.
The
strategy should be taken prior for the research so choose the best suited
according to the purpose.
There
are a number of criteria to consider and these include
i. Relevance
ii. Feasibility
iii. Accuracy
iv. Objectivity
v. Coverage
vi. Ethics
Does
the research you intend to carry out address current issue in a society
a)
Current – commonly talk about and affect people ie environmental degradation,
governance
(Corruption) the impact of
governance on management and sustainable utilization of natural resources
(disease environment and poverty)
b)
Will your research build upon existing knowledge? Is it going to make a
contribution on what is being known?
c)
Are you going to use the existing theory? are specific theory being tested
d)
Is your research coming with new theory?
Is
the question about be done? (Can your research be done?)
Criteria
for feasibility
a)
Time – is there sufficient time for you to do a research, i.e. to collect data,
analyse and come up with results. How much time are you locating in design,
analyse and writing a report.
b) Resources – do you have enough resources to
cover your research (i.e. financial resources)
c)
Accessibility – information can be available but not accessible. The research
design should make sure that information is accessible. Ie one is doing a
research in rain season when roads are not passable. Or assume the information
available is for nationals and not for foreigners.
Criteria for accuracy
a)
Will the research you want to carry out provide true and honest findings?
b)
Precise and detailed data (full and honest answer to questions)
c)
Do you as a researcher focus on vital issue
Criteria
for objectivity
a)
Will the research give you a fair and balanced picture?
b)
Will the research provide an option of free for personal values believes and
background
c)
Will the researcher maintain an open mind about the findings as well as be able
to recognise limitations about the approach taken.
·
You need to question whether the all right things have been included
·
All the questions should cover the issues being investigated ie people and
events. The extent of responses ( the response rate)
·
Ethics has to do rights and feelings affected by research that you conduct.
(Because
of money respondents can give or not give or exaggerate the information)
·
Avoid deceiving people who are going to give you data use an informed concent ( truth information)
·
Avoid misrepresentation
·
Protect the identities of people whom you are conducting a research on.
Geographers
use specialized research methods to study earth features and human activities.
These methods include;
Field study: A technique that relies on direct observation
as the means of learning about the earth’s surface and the patterns resulting
from human activity. Geographers travel to regions to answer specific questions
about the area or to learn about unfamiliar geographic relationships.
Mapping:
This is one of the geographers’ most basic activities. Many aspects of
geographic research can be shown on maps. Maps present in a simplified form
complex pieces of geographic information. They can easily describe the location,
characteristics and patterns of geographic elements.
Interviewing:
Observation alone can not answer all geographic questions. At times geographers
want to study the attitudes people have towards certain places or how their
surroundings is affected by their beliefs and activities. This information can
be obtained by interviewing groups of people. Researches often do not interview
the entire group, instead they interview a portion of the group scientifically
selected to represent the entire population (Sampling).
-
Interviews can be formal when guided or
informal when guided by a topic.
-
They are face to face and telephone
interviews
Advantages
of interviews:
§ Enable
discussion among the researcher and the correspondent
§ Help
to have information on certain groups through telephone interviews
Disadvantages
of interviews
·
Time consuming and costly
·
Inaccuracy of information due to
forgetfulness, shy, or biasness
·
The researcher may employ research
assistants who are not competent.
·
Lack standards during evaluation.
Focus groups:
Acquiring information from a group of 10–20 people. It helps them to understand
and voice some of the geographic problems they face. A group should be
representative of the whole population. A focus group enables people with
different views to discuss their differences, challenge assumptions and come to
a collective understanding of the geographic problems. This method gives very
brief precise and specific information about the problem. They create new
knowledge which was not obtained through other methods.
Quantitative
methods: With the aid of the computer geographers often test their research
by using quantitative (mathematical and statistical) methods. These methods
help to simplify complex information and to present it in a form that is more easily
understood. They also help geographers find the patterns in geographic elements
and determine which factors affecting a particular element are the most
important.
The use of scientific instruments:
This is very crucial to geographic research. Geographers use remote sensing
devices to identify and study hard to reach or very large physical features.
Such devices are instruments that observe and record information from a
distance. These devices include aerial and satellite cameras, infrared (heat
sensitive) films, and radar. These devices record information about weather
systems, patterns of vegetation growth, the existence of pollution, etc. Some instruments measure environmental
characteristics such as weather gauges, which measure and record temperature,
humidity, wind speed and direction and air pressure.
Geography
is a field study subject, concerned with accurate observation, recording and
interpretation of the variable nature of the human and physical landscapes.
The
geographers’ laboratory is in the field, the local environment.
Types of field work:
Field
excursion (Field trip): Refers to the trip round the
locality or further a field in order to visit places of geographical interest.
Students (researchers) observe, listen to lectures by experts (resource
persons). Although it is difficult to structure it has the advantage of bringing
students into reality of the environment. They are given the opportunity to
identify problems of development for later class discussion.
Field
study: Refers to the practice whereby students are taken
to permanent field centers or laboratories, chosen and maintained by geography
departments, for purpose of studying geographic patterns and processes.
Students may closely examine and analyze a piece of landscape to understand
spatial variations. It involves intensive investigation.
Field
research: Refers to fieldwork organized in the
context of problem solving approach. A problem of study is stated. A hypothesis
put forward for testing; data collection; analysis; hypothesis testing,
Conclusion.
10.3
Historical background of Fieldwork in Geography
Change has been present throughout the long development of geography.
Change has been present throughout the long development of geography.
ü There
have been a number of different phases or trends in the discipline.
ü Throughout
all this change over the centuries, however, a few things have remained
constant.
ü the subject matter of geography hasn't really
changed Since
the time of the ancient Greeks, geographers have been concerned with the
Earth's surface as the home of mankind
Something else that has not changed is the fact that geography has
always been a discipline of observation
ü Observation
is simply the most basic way of understanding the fundamental components of
geography
-geographers
have been observers for centuries
-Homer
and other Greeks who observed their surroundings and wrote about them are today
recognized as geographers as much as they are by other disciplines
ü Fieldwork
has evolved from its traditional, observational-based origins to a diversity of
learning and teaching processes that, since the 1960s and 1970s, have been
characterised by increased orientation around study of geographical processes
(cf observation of form) and research and problem-solving approaches. Such
approaches have necessarily demanded development of subject-specific technical
skills, but also the opportunities provided by fieldwork for developing
transferable skills (for example teamwork, leadership) and student employability
were recognised in the 1980s when such skills became explicit learning
objectives of fieldwork (Kent et al, 1997).
ü Observation
has formally been incorporated into geography through fieldwork.
ü fieldwork
is nothing more than systematic observation by a geographer of his or her
subject matter
ü anyone can do fieldwork, and every good
geographer does
Virtually
anyone can do it because fieldwork is, at its most fundamental, just going out
and looking at the land
-all
the training you need is knowing what to look for
-knowing
what to look for involves training in your respective area
-physical
geographers, for example, need to understand geomorphology before going out to
research the erosion pattern of a slope
-economic
geographers need to understand land use types before going out to chart
economic patterns in American cities
Fieldwork
is important to geography because it contributes so fundamentally to
geographical research and to our basic understanding of the Earth's surface.
·
To understand history in its fullest sense, one cannot just read books about
past events or what are commonly called secondary sources
·
To understand geography or do geographic research, one must consult primary sources
in this respect; geographers certainly make use of some of the same primary
sources as researchers in other fields do
·
Geographers doing research spend much time in the archives looking at original
documents like census manuscripts
·
Geography, however, has another primary source that is quite different from
those used in other fields; this, of course, is the landscape
·
The landscape is the primary source of the geographer, whether he or she is a
physical, cultural, or economic geographer
-it
can be rural or urban
-it
contains all of the essential facts of geography and, many would say, the means
of explaining those facts
i.
Be curious and observant
-you
must want to do fieldwork, and you must keep your eyes open
ii. Take clear, organized notes
-fieldwork
is just sightseeing unless you can use the information later
iii. Pay careful attention to your location,
making good use of maps
-no
matter how detailed your observations are, they are of little value in
geography if you cannot link them to a location
-this
is where maps come in handy in the field
-making
notes about a site at its location on a good map lends precision to your
fieldwork
-increasingly,
you can note your location accurately by using GPS
-Global
Positioning System receivers are lightweight and portable
-they
are also becoming quite accurate
-better
models can even record and store data for sample locations; you can later
download that data directly into a GIS
iv. Be consistent: fieldwork is literally data
collection, whether it is soil or plant types or religious patterns, so
consistency is important for accurate results
The
value of good fieldwork will not usually be seen in the field, but will instead
show up later . . . when you analyze your field observations.
o
remember, fieldwork is data collection
o
your observations are thus raw data
o
if you have observed things systematically and recorded these observations
consistently, your analysis of the data will go smoothly
o
you will also be able to do something with your data
-most
basic is mapping similar observations
-then,
interpret and explain the pattern
-finally,
compare the pattern to other patterns
Approaches to Field Work
Historically,
two views have tended to dominate fieldwork, at least in American geography
(Deductive and Inductive Methods).
Deductive
Method
o
one of these was common at the University of Chicago
-in
this view, geographers studied a particular problem in depth and then went into
the field to look for answers to the problem
-this
involved the deductive method
-this
method can obviously work, but it is very easy to go into the field and simply
look until you find what you are looking for.
Inductive
Method
o
another view was held by Carl Sauer at the University of California, Berkeley
-Sauer
was probably the strongest advocate of fieldwork in American geography
-he
made all of his students to fieldwork, mainly in Mexico and South America
-he
himself conducted fieldwork almost every year of his professional life
-he
reputedly once said that any mode of transportation faster than a mule was too
fast for fieldwork, and he preferred walking
-Sauer's
fieldwork philosophy was just the opposite of the Chicago view
-Sauer
felt geographers should identify vague topics
-they
should then conduct thorough, unbiased fieldwork and simply see what problems
and answers the landscape yielded
-this
involved the inductive method
-more
sound logically and scientifically, in many ways
-the
upshot if this was that Sauer send his students into the field with little more
than a notebook
-students
were not told how to do fieldwork, for everyone does it differently
-they
were certainly not told what to look for
-it
was really on the job training
-they
include step-by-step instructions on a wide range of techniques and skills
-they
also include a series of exercises on each of the major topics related to
fieldwork
-there
is also a superb reading list attached to this site
It
is not possible to observe the all population, so we observe the sub set of
population which is called sample.
One
major characteristics of population is that they are never homogeneous. Population
is always heterogeneous. And therefore the value of attributes of which we want
to collect information from is also heterogeneous. So we get a representative
sample to make inferences about a population. And this inference influences the
decision making processes. Example what Tanzanians regional division should be
based on?
There
are two major sampling techniques these are
·
Probability sampling
·
Non probability sampling
A.
PROBABILITY SAMPLING
1.
RANDOM SAMPLING
i.
Simple random sampling
ii.
Stratified random sampling
iii.
Systematic sampling
iv.
Mult stage sampling
B.
NON RANDOM SAMPLING
i.
Cluster sampling
ii.
Judgemental sampling
iii.
Accessibility sampling
iv.
Quarter sampling
C.
Perhaps
the most frequently asked question concerning sampling is, "What size
sample do I need?" The answer to this question is influenced by a number
of factors, including the purpose of the study, population size, the risk of
selecting a "bad" sample, and the allowable sampling error.
This
paper reviews criteria for specifying a sample size and presents several
strategies for determining the sample size.
In
addition to the purpose of the study and population size, three criteria
usually will need to be specified to determine the appropriate sample size: the
level of precision, the level of confidence or risk, and the degree of
variability in the attributes being measured (Miaoulis and Michener, 1976).
Each of these is reviewed below.
The Level of Precision
The
level of precision, sometimes called sampling error, is the range in which the
true value of the population is estimated to be. This range is often expressed
in percentage points, (e.g., ±5 percent), in the same way that results for
political campaign polls are reported by the media. Thus, if a researcher finds
that 60% of farmers in the sample have adopted a recommended practice with a
precision rate of ±5%, then he or she can conclude that between 55% and 65% of
farmers in the population have adopted the practice.
The Confidence Level
The
confidence or risk level is based on ideas encompassed under the Central Limit
Theorem. The key idea encompassed in the Central Limit Theorem is that when a
population is repeatedly sampled, the average value of the attribute obtained
by those samples is equal to the true population value. Furthermore, the values
obtained by these samples are distributed normally about the true value, with
some samples having a higher value and some obtaining a lower score than the true
population value. In a normal distribution, approximately 95% of the sample
values are within two standard deviations of the true population value (e.g.,
mean). In other words, this means that, if a 95% confidence level is selected,
95 out of 100 samples will have the true population value within the range of
precision specified earlier (Figure 1). There is always a chance that the
sample you obtain does not represent the true population value. Such samples
with extreme values are represented by the shaded areas in Figure 1. This risk
is reduced for 99% confidence levels and increased for 90% (or lower)
confidence levels.
Degree of Variability
The
third criterion, the degree of variability in the attributes being measured
refers to the distribution of attributes in the population. The more
heterogeneous a population, the larger the sample size required to obtain a
given level of precision. The less variable (more homogeneous) a population,
the smaller the sample size. Note that a proportion of 50% indicates a greater
level of variability than either 20% or 80%. This is because 20% and 80%
indicate that a large majority do not or do, respectively, have the attribute
of interest. Because a proportion of .5 indicates the maximum variability in a
population, it is often used in determining a more conservative sample size,
that is, the sample size may be larger than if the true variability of the population
attribute were used.
There
are several approaches to determining the sample size. These include using a census for small populations, imitating a
sample size of similar studies, using published tables, and applying formulas
to calculate a sample size. Each strategy is discussed below.
Using
a Census for Small Populations
One
approach is to use the entire population as the sample. Although cost
considerations make this impossible for large populations, a census is
attractive for small populations (e.g., 200 or less). A census eliminates
sampling error and provides data on all the individuals in the population. In
addition, some costs such as questionnaire design and developing the sampling
frame are "fixed," that is, they will be the same for samples of 50
or 200. Finally, virtually the entire population would have to be sampled in
small populations to achieve a desirable level of precision.
Using
a Sample Size of a Similar Study
Another
approach is to use the same sample size as those of studies similar to the one
you plan. Without reviewing the procedures employed in these studies you may
run the risk of repeating errors that were made in determining the sample size
for another study. However, a review of the literature in your discipline can
provide guidance about "typical" sample sizes which are used.
Using
Published Tables
A
third way to determine sample size is to rely on published tables which provide
the sample size for a given set of criteria. Table 1 and Table 2 present sample
sizes that would be necessary for given combinations of precision, confidence
levels, and variability. Please note two things. First, these sample sizes reflect
the number of obtained responses, and not necessarily the number of surveys
mailed or interviews planned (this number is often increased to compensate for
non response). Second, the sample sizes in Table 2 presume that the attributes
being measured are distributed normally or nearly so. If this assumption cannot
be met, then the entire population may need to be surveyed.
Size
of
|
Sample
|
Size
(n) for
|
Precision
(e) of
|
||
Populatin
|
±3%
|
±5%
|
±7%
|
±10%
|
|
500
|
A
|
222
|
145
|
83
|
|
600
|
A
|
240
|
152
|
86
|
|
700
|
A
|
255
|
158
|
88
|
|
800
|
A
|
267
|
163
|
89
|
|
900
|
A
|
277
|
166
|
90
|
|
1,000
|
A
|
286
|
169
|
91
|
|
2,000
|
714
|
333
|
185
|
95
|
|
3,000
|
811
|
353
|
191
|
97
|
|
4,000
|
870
|
364
|
194
|
98
|
|
5,000
|
909
|
370
|
196
|
98
|
|
6,000
|
938
|
375
|
197
|
98
|
|
7,000
|
959
|
378
|
198
|
99
|
|
8,000
|
976
|
381
|
199
|
99
|
|
9,000
|
989
|
383
|
200
|
99
|
|
10,000
|
1,000
|
385
|
200
|
99
|
|
15,000
|
1,034
|
390
|
201
|
99
|
|
20,000
|
1,053
|
392
|
204
|
100
|
|
25,000
|
1,064
|
394
|
204
|
100
|
|
50,000
|
1,087
|
397
|
204
|
100
|
|
100,000
|
1,099
|
398
|
204
|
100
|
|
>100,000
|
1,111
|
400
|
204
|
100
|
|
Size of
|
Sample
|
Size (n) for precision of
|
||
Population
|
±5%
|
±7%
|
±10%
|
|
100
|
81
|
67
|
51
|
|
125
|
96
|
78
|
56
|
|
150
|
110
|
86
|
61
|
|
175
|
122
|
94
|
64
|
|
200
|
134
|
101
|
67
|
|
225
|
144
|
107
|
70
|
|
250
|
154
|
112
|
72
|
|
275
|
163
|
117
|
74
|
|
300
|
172
|
121
|
76
|
|
325
|
180
|
125
|
77
|
|
350
|
187
|
129
|
78
|
|
375
|
194
|
132
|
80
|
|
400
|
201
|
135
|
81
|
|
425
|
207
|
138
|
82
|
|
450
|
212
|
140
|
82
|
|
Using
Formulas to Calculate a Sample Size
Although
tables can provide a useful guide for determining the sample size, you may need
to calculate the necessary sample size for a different combination of levels of
precision, confidence, and variability. The fourth approach to determining
sample size is the application of one of several formulas
Ø A questionnaire is a written set of questions
which you give to a large number of people in order to collect information
· The goals of
the study should be well defined. They should be expressed in a few clear and
concise sentences to make the design of the questionnaire considerably easier.
· As a general
rule, with only a few exceptions, long questionnaires get less response than
short questionnaires. Keep your questionnaire short to have high response rate
· One important
way to assure a successful survey is to include other experts and relevant
decision-makers in the questionnaire design process. Their suggestions will
improve the questionnaire and they will subsequently have more confidence in
the results
·
Formulate a plan for doing the statistical analysis during the design stage of
the project. Know how every question will be analyzed and be prepared to handle
missing data. If you cannot specify how you intend to analyze a question or use
the information, do not use it in the survey.
·
Give your questionnaire a title that is short and meaningful to the respondent.
A questionnaire with a title is generally perceived to be more credible than
one without
·
Use simple and direct language. The questions must be clearly understood by the
respondent. The wording of a question should be simple and to the point
·
Place the most important items in the first half of the questionnaire
·
Items on a questionnaire should be grouped into logically coherent sections.
Grouping questions that are similar will make the questionnaire easier to complete,
and the respondent will feel more comfortable
There
are good and bad questions. The qualities of a good question are as follows:
1.
Evokes the truth. Questions must be non-threatening. Anonymous questionnaires
that contain no identifying information are more likely to produce honest
responses than those identifying the respondent. If your questionnaire does
contain sensitive items, be sure to clearly state your policy on
confidentiality.
2.
Asks for an answer on only one dimension. A good question asks for only one
"bit" of information. The purpose of a survey is to find out
information. A question that asks for a response on more than one dimension
will not provide the information you are seeking. For example, another
questionnaire asks, "Were you satisfied with the quality of our food and
service?" Again, if the respondent answers "no", there is no way
to know whether the quality of the food, service, or both were unsatisfactory.
3.
Can accommodate all possible answers. Asking a question that does not
accommodate all possible responses can confuse and frustrate the respondent.
For example, consider the question: What is your occupation: a) Teacher b)
Nurse……………
·
Questionnaires
are very cost effective when compared to face-to-face interviews. This
is especially true for studies involving large sample sizes and large
geographic areas. Written questionnaires become even more cost effective as the
number of research questions increases.
·
Questionnaires
are easy to analyze. Data entry and tabulation for nearly all surveys
can be easily done with many computer software packages.
·
Questionnaires are familiar to most people.
Nearly everyone has had some experience completing questionnaires and they
generally do not make people fearful.
·
Questionnaires
reduce bias. There is uniform question presentation and no middle-man
bias. The researcher's own opinions will not influence the respondent to answer
questions in a certain manner. There are no verbal or visual clues to influence
the respondent.
·
Questionnaires
are less intrusive than telephone or face-to-face surveys. When a
respondent receives a questionnaire in the mail, he is free to complete the
questionnaire on his own time-table. Unlike other research methods, the
respondent is not interrupted by the research instrument.
·
One major disadvantage of written questionnaires is the possibility of low response rates.
Low response is the curse of statistical analysis. It can dramatically lower
our confidence in the results. Response rates vary widely from one
questionnaire to another (10% - 90%), however, well-designed studies
consistently produce high response rates.
·
Another disadvantage of questionnaires is the inability to probe responses.
Questionnaires are structured instruments. They allow little flexibility to the
respondent with respect to response format. In essence, they often lose the
"flavor of the response" (i.e., respondents often want to qualify
their answers). By allowing frequent space for comments, the researcher can
partially overcome this disadvantage. Comments are among the most helpful of
all the information on the questionnaire, and they usually provide insightful
information that would have otherwise been lost.
·
Nearly ninety percent of all communication is visual. Gestures and other visual cues
are not available with written questionnaires. The lack of personal
contact will have different effects depending on the type of information being
requested. A questionnaire requesting factual information will probably not be
affected by the lack of personal contact. A questionnaire probing sensitive
issues or attitudes may be severely affected.
·
When returned questionnaires arrive in the mail, it's natural to assume that
the respondent is the same person you sent the questionnaire to. This may not
actually be the case. Many times business questionnaires get handed to other
employees for completion. Housewives sometimes respond for their husbands. Kids
respond as a prank. For a variety of reasons, the respondent may not be who you
think it is. It is a confounding error inherent in questionnaires.
·
Finally,
questionnaires are simply not suited for some people. For example, a
written survey to a group of poorly educated people might not work because of
reading skill problems. More frequently, people are turned off by written
questionnaires because of misuse.
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