Instrument is the general term that researchers use for a measurement device (survey, test, questionnaire, etc.). To help distinguish between instrument and instrumentation, consider that the instrument is the device and instrumentation is the course of action (the process of developing, testing, and using the device) There are several criteria to be considered when deciding on a data- collection-collection instrument, these include: Practicality of the instrument Reliability of the instrument Validity of the instrument. Practicality of the Instrument Before the researcher examines the reliability and validity of an instrument should be asked about the practicality of the tool for the particular study that is being planned The practicality of an instrument concerns its cost and appropriateness for study population. How much will the instrument cost? How long will it take to the instrument?
DATA-COLLECTION PROCESS There are five important questions to ask when the researcher is in the process of collecting data: This question calls for a decision to be made about the type of data that is being sought. Example Is the study designed to measure knowledge, attitudes, or behaviors? The type of data that is being sought, of course, will also govern the how, who, where, and when of the data- collection process. The answers to all of these questions are interrelated, and it may be difficult to determine which question should be answered first.
Methods of Data collection: Self-report questionnaires Interviews Physiological measures Attitude scales Psychological tests Observational methods Other types Questionnaires have probably been the most frequently reported of data collection in published nursing studies. Questionnaire design is a multi-step process. Questionnaires allow collection of both subjective and objective data in a large sample of the study population in order to obtain results that are statistically significant, specially when resources are limited. It is a good tool for the protection of the privacy of the participants. The validity of data and information depends on the honesty of the respondent. The questionnaires can measure both qualitative and quantitative data, but is it more appropriate for quantitative data collection.