Reasons for validating evaluation instruments

15-Jan-2016 11:10 by 7 Comments

Reasons for validating evaluation instruments

Recall that a sample should be an accurate representation of a population, because the total population may not be available.An instrument that is externally valid helps obtain population generalizability, or the degree to which a sample represents the population.

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In other words, do the measures (questions, observation logs, etc.) accurately assess what you want to know?(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: is the extent to which an instrument measures what it is supposed to measure and performs as it is designed to perform.It is rare, if nearly impossible, that an instrument be 100% valid, so validity is generally measured in degrees.

As a process, validation involves collecting and analyzing data to assess the accuracy of an instrument.

There are numerous statistical tests and measures to assess the validity of quantitative instruments, which generally involves pilot testing.

The remainder of this discussion focuses on external validity and content validity. Establishing eternal validity for an instrument, then, follows directly from sampling.

This is particularly important with achievement tests.

Consider that a test developer wants to maximize the validity of a unit test for 7th grade mathematics.

This would involve taking representative questions from each of the sections of the unit and evaluating them against the desired outcomes. Does the instrument consistently measure what it is intended to measure?