Reliability refers to the consistency of a measure or study. Research is reliable if it produces the same results when repeated under the same conditions. Types include test retest reliability (consistency over time), inter rater reliability (agreement between observers), and internal reliability (consistency within a test). Reliability is improved through standardised procedures, clear operationalised variables, trained researchers, and replication.

Validity in Psychological Research
Explore the importance of validity in psychological investigations. Validity refers to how accurately a test or study measures what it intends to measure. Internal validity assesses whether results are caused by the independent variable, while external validity considers whether findings can be generalised to real-life and broader populations.