Instrumentation

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).

Instruments fall into two broad categories, researcher-completed and subject-completed, distinguished by those instruments that researchers administer versus those that are completed by participants. Researchers chose which type of instrument, or instruments, to use based on the research question. Examples are listed below:

Researcher-completed Instruments	Subject-completed Instruments
Rating scales	Questionnaires
Interview schedules/guides	Self-checklists
Tally sheets	Attitude scales
Flowcharts	Personality inventories
Performance checklists	Achievement/aptitude tests
Time-and-motion logs	Projective devices
Observation forms	Sociometric devices

Usability

Usability refers to the ease with which an instrument can be administered, interpreted by the participant, and scored/interpreted by the researcher. Example usability problems include:

1. Students are asked to rate a lesson immediately after class, but there are only a few minutes before the next class begins (problem with administration).
2. Students are asked to keep self-checklists of their after school activities, but the directions are complicated and the item descriptions confusing (problem with interpretation).
3. Teachers are asked about their attitudes regarding school policy, but some questions are worded poorly which results in low completion rates (problem with scoring/interpretation).

Validity and reliability concerns (discussed below) will help alleviate usability issues. For now, we can identify five usability considerations:

1. How long will it take to administer?
2. Are the directions clear?
3. How easy is it to score?
4. Do equivalent forms exist?
5. Have any problems been reported by others who used it?

It is best to use an existing instrument, one that has been developed and tested numerous times, such as can be found in the Mental Measurements Yearbook. We will turn to why next.