Questionnaires, Interviews and Sampling – Fieldwork Techniques (Senior 4 Geography) | Ganzaa

Fieldwork Techniques

Lessons

Senior 4 · Geography

Fieldwork Techniques

4 lessons

Lesson 2 of 4

Questionnaires, Interviews and Sampling

25 min

A questionnaire that would fail

Observation and measurement show what is in a place. To learn why (why traders come to a market, why a family moved to town, why a farmer chose terraces) you must ask people. A class preparing a study of the traders at a market wrote the draft in Figure 3. Each question looks harmless, yet four of them would give answers that are biased, refused or impossible to analyse.

Figure 3: a first draft written by a class planning a market study (illustrative). Before reading on, decide what is wrong with questions 2 to 5.

Definition

Questionnaire: a set of written questions, asked in the same order and words to every respondent, so that the answers can be counted and compared. A respondent is the person who answers.

Closed question: the respondent chooses from given answers ("How often do you come to this market? Daily / weekly / monthly"). Open question: the respondent answers in his or her own words ("What problems do you face here?").

Example: question 4 in Figure 3 could become a closed question with tick boxes for each crop.

What is wrong with the draft

Question	Fault	Better version
2	Leading: it pushes the respondent towards "yes".	"How does the new market building compare with the old one? Better / the same / worse / don't know"
3	Sensitive: many traders will refuse or guess, and it can damage trust.	Leave it out, or ask about busy and quiet days instead: "Which days are busiest for you?"
4	Double: a trader who sells beans but not maize cannot answer "yes" or "no".	"Which of these do you sell? Tick all that apply: beans / maize / sorghum / other"
5	Jargon and too broad: the words are a geographer's, not a trader's.	"Where do you buy most of the goods you sell? Name the place."

Testing a questionnaire on a few people before the real survey, a pilot study (next lesson), is how such faults are found in time.

Tip

A good questionnaire is short (one side of paper, about 10 minutes), starts with easy questions, uses mostly closed questions so answers can be counted, adds one or two open questions for reasons, and is written in the respondent's language. In most of Rwanda that means a Kinyarwanda version, translated and checked before the fieldwork.

Interviews

An interview is a conversation in which the researcher asks questions face to face (or by phone) and records the answers. It goes deeper than a questionnaire because the interviewer can explain a question and ask follow-up questions.

Structured interview: fixed questions in a fixed order, like a spoken questionnaire.
Semi-structured interview: a list of topics, with freedom to follow up interesting answers.
Unstructured interview: an open conversation around one theme.
Key informant interview: with a person who knows the topic well, such as a sector agronomist, the leader of a farming cooperative, or the manager of a market.
Focus group discussion: 6 to 10 people discuss a question together, guided by the researcher.

Definition

Interview: collecting information by asking questions directly and recording the answers. Key informant: a person chosen because of special knowledge of the topic.

Example: interviewing the manager of a fish landing site about how the catch has changed since the closed season was introduced.

Method	Advantages	Disadvantages
Questionnaire	Many respondents in a short time; the same questions for all, so answers can be counted and graphed; respondents can stay anonymous	Rigid: no follow-up; misunderstood questions give wrong answers; self-completed forms need literate respondents and many are not returned
Interview	Depth and reasons; questions can be explained; works with people who cannot read; the interviewer also observes	Slow, so few people are reached; the interviewer's manner can influence answers; answers are harder to compare and count

Important

Ethics: rules that protect the people you study. Get permission from the school and, for a survey in a village or market, inform the local authorities (the cell or sector office) and the market management. Explain who you are and why you are asking. Ask each person's consent, and accept a refusal politely. Do not record names unless needed, and keep answers confidential. Never ask children questions without the consent of a parent or teacher, and never photograph people without asking.

Sampling: studying a part to learn about the whole

A market may have 150 traders; a hillside thousands of square metres; a sector thousands of households. Nobody can study them all, so the fieldworker studies a sample and uses it to describe the whole. The sample is only useful if it is representative, free from the bias that comes from choosing the friendliest traders or the nearest houses.

Definition

Population (in sampling): every member of the group being studied, for example all 150 traders. Sample: the part that is actually studied. Sampling frame: the list from which the sample is drawn, such as the market's list of stalls.

Random sampling: every member has an equal chance of being chosen (numbers drawn from a hat, or random numbers from a phone). Systematic sampling: members are chosen at a regular interval, every $k$ th item, after a random start. Stratified sampling: the population is divided into groups (strata), and each group is sampled in proportion to its size.

Figure 4: random, systematic and stratified sampling of an area. In the stratified panel, 60% of the area is farmland, so it gets about 60% of the points (5 of 8 here).

In physical geography the same ideas are applied in space: point sampling (measuring at chosen points), line sampling (measuring at intervals along a line, a transect, for example from a hilltop to a valley floor), and area sampling (counting inside a frame called a quadrat).

Worked example 1: a stratified sample of traders

Problem. A market has 150 traders: 75 sell food, 45 sell clothes and 30 sell hardware. A class can interview 30. How many should come from each group?

Solution. The number from group $i$ is its share of the population times the sample size:

n_i = \frac{N_i}{N} \times n

n_{\text{food}} = \frac{75}{150} \times 30 = 15, \quad n_{\text{clothes}} = \frac{45}{150} \times 30 = 9, \quad n_{\text{hardware}} = \frac{30}{150} \times 30 = 6

Check: $15 + 9 + 6 = 30$ . Within each group, the traders are then chosen at random.

Worked example 2: systematic samples on a list and on the ground

(a) A village list has 240 households and you need 20. The sampling interval is

k = \frac{N}{n} = \frac{240}{20} = 12

Pick a random start from 1 to 12, say 7. The sample is households 7, 19, 31, … The 20th is $7 + 19 \times 12 = 235$ , still on the list.

(b) A transect runs 150 m down a slope and soil is sampled every 10 m, starting at 0 m. The number of sampling points is

\frac{150}{10} + 1 = 16

Forgetting the "+1" for the starting point is a common slip.

Warning

Systematic samples can fall into step with a pattern. If houses along a road alternate between a shop and a home, every 2nd building will always be the same kind. Look at the area first, and switch to random or stratified sampling if a regular pattern could bias the result.

Geography In Action: "Urban Fieldwork GCSE Geography Revision: Video 3, Urban Fieldwork Sampling Methods in Stratford". A teacher explains random, systematic and stratified sampling as used in a real urban study. Note the reasons he gives for choosing one method over another.

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Practice

Explain the difference between an open and a closed question, with one example of each about transport to a market.
Name the fault in each question and rewrite it: (a) "Most people agree that terraces are useful, don't they?" (b) "Do you grow and sell coffee?"
A school has 220 students in S4, 200 in S5 and 180 in S6. Find the number from each class in a stratified sample of 60.
A list of 360 households must give a systematic sample of 24. Find the sampling interval and, with a random start of 5, the last household chosen.
A transect is 2.4 km long and land use is recorded every 200 m, including both ends. How many points are recorded?
Give two advantages of an interview over a questionnaire, and two of a questionnaire over an interview.
A study asks how land use changes from a hilltop to a valley floor. Which sampling method would you choose? Justify your choice.

Show answersHide answers

Closed: answers are given ("How did you come today? Walk / bicycle / moto / bus"). Open: own words ("Why did you choose this market?").
(a) Leading: "Are terraces useful on your farm? Yes / no / not sure; why?" (b) Double: "Do you grow coffee?" and "Do you sell coffee?" as two questions.
$\frac{220}{600} \times 60 = 22$ ; $\frac{200}{600} \times 60 = 20$ ; $\frac{180}{600} \times 60 = 18$ . Check: 60.
$k = \frac{360}{24} = 15$ ; the last is $5 + 23 \times 15 = 350$ .
$\frac{2400}{200} + 1 = 13$ points.
Interview: follow-up questions give reasons; works with people who cannot read; questions can be explained. Questionnaire: reaches many people quickly; identical questions give answers that can be counted and compared; respondents can be anonymous.
Systematic line sampling along a transect from the hilltop to the valley floor, recording land use at equal intervals. It covers every part of the slope in order, so changes with height show up clearly; random points might miss a narrow zone such as the valley floor.

Quick check

Which of these questions for traders is a leading question?

Key points

Questionnaires reach many people with identical, countable questions; avoid leading, double, sensitive and jargon questions.
Interviews give depth and reasons from fewer people; key informants and focus groups are special forms.
Sampling must be representative: random, systematic ( $k = \frac{N}{n}$ ) or stratified ( $n_i = \frac{N_i}{N}\times n$ ); point, line and area sampling apply them on the ground.
Ethics: permission, consent, confidentiality and respect.

Sources and credits

Written by Ganzaa. Figures 3 and 4, the worked examples and the exercises were drawn and written by Ganzaa; the questionnaire draft is illustrative.

Photos: Trading in Nyamata market, MBERABAHIZI, CC0; Vegetation ecologist demonstrates how to set up a plot, Alice Wondrak-Biel, US National Park Service, public domain; both via Wikimedia Commons.

Video: "Urban Fieldwork GCSE Geography Revision: Video 3, Urban Fieldwork Sampling Methods in Stratford", Geography In Action, embedded from YouTube.

1A questionnaire that would fail

2What is wrong with the draft

3Interviews

4Sampling: studying a part to learn about the whole

A questionnaire that would fail

What is wrong with the draft

Interviews

Sampling: studying a part to learn about the whole