6. questionnaire design and validation by dr bony (14 november 2013).pptx

BONY WIEM LESTARIEPIDEMIOLOGY AND BIOSTATISTICS DEPARTMENT

2012

QUESTIONNAIRE DESIGN AND VALIDATION

1. Distinguish between various stages in questionnaire design.

2. Demonstrate appropriate techniques for wording questions

3. Validity and Reliability of measurement tool

4. Identify appropriate delivery format of certain questionnaire

Learning Objectives:

What is Questionnaire

?

A TOOL FOR COLLECTING INFORMATION TO DESCRIBE, COMPARE, EXPLAIN, KNOWLEDGE, ATTITUDES, BEHAVIORS, AND/OR DEMOGRAPHIC CHARACTERISTICS ON A PARTICULAR TARGET GROUP

1. Self administered (mailed or personal contact)

2. In person (face-to-face) interviews

3. Telephone interviews

Questionnaire General Format:

Types of Questions:

1. Open-ended questions• Permit free response which should be

recorded in the respondents’ own words.

2. Closed questions• Have a list of possible options or

answers from which the respondents must choose.

Identify: (Self learning)

1. Advantages & disadvantages of open-ended questions

2. Advantages & disadvantages of closed questions

Steps in Designing A Questionnaire

1. Content Take your objectives and variables as a starting point

2. Formulating questions– Formulate one or more questions that will provide the

information needed for each variable– Check whether each question measures one thing at a time– Avoid leading questions– Avoid words with double or vaguely defined meanings or

that emotionally laden– Ask sensitive questions in a socially acceptable way

Steps in Designing A Questionnaire

3. Sequencing the questions– Design your interview schedule or questionnaire to

be ‘informant friendly’– Use simple, everyday language

4. Formatting the questionnaire5. Translation

If interviews will be conducted in one or more local languages, the questionnaire should be translated in order to standardise the way questions will be asked.

Steps in Questionnaire Development: (Cohen)

Conceptualization:abstract construct – conceptual definition – operationalization - indicator

Constructing

Testing

Analysis

Revising

Penting !!!

Questionnaire is a tool:

• The quality of a measurement: validity and reliability

Validity: • the extent to which a test measures what it is

intended to measure• Free of systematic error• Accuracy

Questionnaire is a tool:

Reliability:• The degree to which a variable has nearly the same

value when measured several times• Free of random error (chance)• Precision• Also called reproducibility, consistency• Assessing precision (reproducibility of repeated

measurement):– Within – between observer– Within – between instruments

Reliability:

• Reliability coefficient ~ correlation coefficient (0 – 1)• A questionnaire is reliable when the

minimum reliability coefficient is 0.7

Assessing Validity:

• Criterion validity (predictive and concurrent)depending on whether the criterion refers to a current or future assessment

• Construct validityassembly evidence to support or refute a complex scientific theory and to show under what circumstances it holds true

Assessing Validity:

• Content validity– refers to comprehensiveness– how adequate the sampling of questions reflects

the aims of the index that were specified in the conceptual definition of its scope

FINAL REMARKS:

• prior to using a questionnaire it has to be established that the instrument is valid and reproducible in the context (i.e. population, setting and study design) in which it is going to be employed.

• conceptually comparable (conceptual equivalence)• developing a new questionnaire is very time-

consuming• burden on respondents• practical aspects of the study

REFERENCES:

1. Measuring Health: A Guide to Rating Scales and Questionnaire. Ian McDowell and Claire Newell. 1996.

2. Psychological Testing: Design, Analysis and Use. Lisa Friedenberg. 1995.

3. Designing and Conducting Health System Research Projects. KIT Publishers. WHO. 2003

What’s Your Message?THANK YOU