Reliability and Validity

Reliability and validity are essential in terms of observation and measurement as it relates to human services research. In order to ensure this particular research has legitimacy it is vital that testing and research is consistent and specific. This paper will define and describe the types of reliability and validity and provide examples of each as it relates to human services research. It will also provide examples of how data collection methods and instruments are used in relation to human services research as well as managerial research.
Reliability is an important criterion in regards to research and refers to the degree of consistency or stability of a measure. Reliability refers to consistency, stability or dependability (Rosnow & Rosenthal, 2008). High reliability of a particular measure will be one that produces similar results under consistent conditions. There are four forms of reliability used in human services research and are as follows: alternate-form reliability, internal-consistency reliability, item-to-item reliability and test-retest reliability.

Alternate-form reliability refers to the degree of relatedness of different forms of the same test. In other words, it measures results obtained by alternate versions of the same test in order to determine equivalence. An example of alternate-form reliability as it pertains to human services research would be tests given to develop national aptitude tests. Both tests (Form A and Form B) must have conditions that involve the same construct and knowledge base. Each test is given to the same group of individuals and both scores are correlated and used to determine the reliability of the test. The test that yields the most consistent answers is then used. Internal-consistency reliability, also known as reliability of components, is the overall degree of relatedness of all items between two raters (Rosnow & Rosental). This form of reliability is very useful in human services research when using