Internal validity in Research

A research study or experiment has internal validity if the outcome is a result of the variables that are measured, controlled or manipulated. Internal validity is only relevant in studies that try to establish a causal relationship. For studies that assess the effects of social programs or interventions, internal validity is the primary consideration. The main question in internal validity is whether the observed changes can be directly attributed to the program or intervention that was implemented and not some other factor. There are eight threats to internal validity. These are criticisms that critics will raise when you try to conclude that your program caused the out come. The eight threats are history, maturation, testing, selection bias, statistical regression, instrumentation, selection maturation and mortality. The first threat I will discuss will be history.
History refers to the idea that something or some event in the subject’s life that happened before the study ...