QUESTIONNAIRE CONSTRUCTION

CONSTRUCTION OF QUESTIONNAIRE

– Administration Method• Deciding which questionnaire to use-

– Closed or open ended, – Self or interviewer administered

– Questionnaire construction• Question wording

– short and simple– Avoid negative questions – Avoid Prestige Bias – Use indirect questions

CONSTRUCTION OF QUESTIONNAIRE

• Question Sequence– Questions should flow logically from one to the next.– The researcher must ensure that the answer to a question is

not influenced by previous questions.– Questions should flow from the more general to the more

specific.– Questions should flow from the least sensitive to the most

sensitive.– Questions should flow from factual and behavioral questions

to attitudinal and opinion questions.– Questions should flow from unaided to aided questions.

CONSTRUCTION OF QUESTIONNAIRE

• Questionnaire Pre-testing(Pilot study)• This means that you must test it out to see if it is

obtaining the result you require. • This is done by asking people to read it through and see

if there are any ambiguities which you have not noticed.

• They should also be asked to comment about the length, structure and wording of the questionnaire

• Alter the questions accordingly

Guidelines for Constructing a Questionnaire

1. Simple and concise language2. Realistic demand3. Understanding of the questions4. One dimensional question5. No escape route6. Specific questions not general7. No suggestive questions8. Polite language9. Straightforward questions10. Questions in right order11. Neat and tidy questionnaire12. Pre-test

VALIDATION OF QUESTIONNAIRE

Validation involves establishing that the instrument produces data that are reliable and true. There are a number of ways to define this, some of which outlined below.

– Reliability: the degree to which a questionnaire will produce the same result if administered again, or the “test-retest” concept. It is also a measure of the degree to which a questionnaire can reflect a true change.

– Validity: the degree to which a questionnaire reflects reality. There are a number of different facets to validity.

• Internal validity• External Validity

VALIDATION OF QUESTIONNAIRE

– Sensitivity: the degree to which the instrument can identify a true positive, e.g., accurately identify a person who does have the condition.

– Specificity: similar to sensitivity, this is the degree to which the instrument can identify a true negative, e.g., correctly identify the people who do not have the disease. Sensitivity and specificity are another side of the coin from internal validity.

– Discriminant validity: the ability of the questionnaire to detect true differences between groups

Sampling Plan

• Sampling is concerned with the selection of a subset of individuals from within a population to estimate characteristics of the whole population.

Procedure for drawing sample

Judgment Sampling

Purposive Sampling

Convenience Sampling

Systematic Sampling

Stratified Random

Simple Random

Snowball SamplingArea Sampling

Cluster SamplingQuota Sampling

Non-probabilityProbability Sampling

Sampling Methods

Probability Sampling (random/choice)• Simple Random Sampling

– Select a numbers in randomly– Probability of selection of each unit=1/N

• Stratified Sampling– Population is divided in to different set of

strata(homogeneous)(rural, urban, semi urban)• Systematic sampling

Sampling interval width, I=N/n, 800/40=20• Cluster sampling

Population is divided into different clusters(heterogeneous)• Area sampling

• Some graphical sub division

Non-Probability Sampling(calculated)

• Convenience sampling– Interviewers decide the choice of sampling units based on their

convenience• Judgment sampling

– Sample units are selected on the advice of some expert or by institutions/opinions etc.

• Quota sampling– Population is classified into a number of groups based on some

criterion, (age of members of population, old age, middle age, )• snowball sampling

– Select samples in randomly and additional samples will select based on referrals of those initial samples.