Written by Jack R. Fraenkel and Norman E. Wallen in How to Design and Evaluate Research in Education. McGraw-Hill.2009
A. INSTRUMENTATION
The term instrumentation refers to the entire process of collecting data in a research investigation.
B. WAYS TO CLASSIFY INSTRUMENTS
Research instruments can be classified in many ways. Some of the more common are in terms of who provides the data, the method of data collection, who collects the data, and what kind of response they require from the subjects. Research data are obtained by directly or indirectly assessing the subjects of a study. Self-report data are provided by the subjects of a study themselves. Informant data are provided by other people about the subjects of a study.
C. TYPES OF INSTRUMENTS
There are many types of researcher-completed instruments. Some of the more commonly used are rating scales, interview schedules, observation forms, tally sheets, flowcharts, performance checklists, anecdotal records, and time-and-motion logs. Many types of instruments are completed by the subjects of a study rather than the researcher. Some of the more commonly used of this type are questionnaires; self-checklists; attitude scales; personality inventories; achievement, aptitude, and performance tests; and projective and sociometric devices.
The types of items or questions used in subject-completed instruments can take many forms, but they all can be classified as either selection or supply items. Examples of selection items include true-false items, multiple-choice items, matching items, and interpretive exercises. Examples of supply items include short-answer items and essay questions. An excellent source for locating already available tests is the ERIC database. Unobtrusive measures require no intrusion into the normal course of affairs.
D. VALIDITY AND RELIABILITY
An important consideration in the choice of a research instrument is validity: the extent to which results from it permit researchers to draw warranted conclusions about the characteristics of the individuals studied. A reliable instrument is one that gives consistent results.
E. OBJECTIVITY AND USABILITY
Whenever possible, researchers try to eliminate subjectivity from the judgments they make about the achievement, performance, or characteristics of subjects. An important consideration for any researcher in choosing or designing an instrument is its ease of use.
