Questionnaires are employed to collect data from 2,856 Thai manufacturing
firms. The questionnaire provides an important data quality to be analyzed for
presenting finding which is essential to confidences. The research collected data by
questionnaires established from constructs of conceptual framework and then they are
operationalized to variables that can be observed in reality of each construct. A
construct can be divided into various dimensions which are measured by multi-items
adopted or adapted and identified by the items to measure the construct appropriately. If
items cannot measure fit to the construct, they should be constructed as new items
(Churchill, 1979). Measuring items are anchored by five-point Likert scale ranging from
1=strongly disagree to 5=strongly agree.
Validity and reliability of a questionnaire as qualities of good instrument from
pilot test from 30 Thai manufacturing firms are tested by factor analysis and Cronbach’s
Alpha, respectively to revise the questionnaire to make sure its validity and reliability.
Validity and Reliability
Validity. The validity of an instrument is the power of indicating cause-effect
relationship (internal validity) and generalizability to the external environment (external