Research Behavioral Measures
In research behavioral measures are tests and methods used to gain information from a subject of study. Psychological measures typically come from one of three categories.
Self-report measures are oral or written accounts from the subject themselves. Examples are questionnaires or interviews. Problems can arise from self-report measures in that people may not be honest due to social desirability such as not reporting the true amount of fast food they eat in order to impress the experimenter. In some cases people may not be aware they are being dishonest but are self-delusional in judgement of themselves.
Another type of measure is behavioral and that is when observation of behaviors in a subject is recorded by researchers. This can occur in a field or a lab setting. A problem with this type of measure is that you have to train coders, which are the researchers that are counting the behavior. If you use multiple coders (which is usually a good idea) you have to train multiple people and do tests to make sure they are observing and counting in a consistent manner (this is called inter-rater reliability).
The third most common type of measure used in psychology is physiological which is collecting measurements of body responses n(like heart rate and breathing rate) during varying conditions. A common example of this would be a polygraph (or 'lie detector') test. In most research designs a combination of multiple measures are used in order to have a wider scope on the subject being studied.