Bill Huitt, John Hummel, and Dan Kaeck
Department of Psychology
Valdosta State University

 

Science: A way of knowing

There are a variety of ways of knowing whether or not something is true. Science is one of those ways; scientists have established a set of rules and methodology by which truth is verified (Kuhn, 1962). The process of science generally follows a paradigm that defines the rules and describes procedures, instrumentation and methods of interpretation of data (Wilber, 1998). The results of science are formulated into a hierarchy of increasing complexity of knowledge: facts, concepts, principles, theories, and laws. When engaged in the process of science, scientists formulate hypotheses or educated guesses about the relationships between or among different facets of knowledge.

Assessment, measurement, research, and evaluation are part of the processes of science and issues related to each topic often overlap. Assessment refers to the collection of data to describe or better understand an issue, measurement is the process of quantifying assessment data, research refers to the use of data for the purpose of describing, predicting, and controlling as a means toward better understanding the phenomena under consideration, and evaluation refers to the comparison of data to a standard for the purpose of judging worth or quality. Assessment and/or measurement are done with respect to variables (phenomena that can take on more than one value or level). For example, the variable "gender" has the values or levels of male and female and data could be collected relative to this variable. Data on variables are normally collected by one or more of four methods: paper/pencil, systematic observation, participant observation, and clinical. Three types of research studies are normally performed: descriptive, correlational, and experimental.

Collecting data (assessment), quantifying that data (measurement), making judgments (evaluation), and developing understanding about the data (research) always raise issues of reliability and validity. Reliability attempts to answer concerns about the consistency of the information (data) collected, while validity focuses on accuracy or truth. The relationship between reliability and validity can be confusing because measurements (e.g., scores on tests, recorded statements about classroom behavior) can be reliable (consistent) without being valid (accurate or true). However, the reverse is not true: measurements cannot be valid without being reliable.

The same statement applies to findings from research studies. Findings may be reliable (consistent across studies), but not valid (accurate or true statements about relationships among "variables"), but findings may not be valid if they are not reliable. At a miniumum, for an instrument to be reliable a consistent set of data must be produced each time it is used; for a research study to be reliable it should produce consistent results each time it is performed.

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