Glossary H

Glossary H

- History as a threat to internal validity : History as a threat to internal validity is a change in the dependent variable due to the occurrence of an event between the testing of levels of the independent variable.

History effects refers to a possible confound in research that inadvertently takes place between measurements because of historical changes in the participant

- Histrionic personality disorder : Histrionic personality disorder refers to Cluster B (dramatic, emotional, or erratic) personality disorder involving a pervasive pattern of excessive emotionality and attention seeking. It is a personality disorder characterized by exaggerated emotional reactions, approaching theatricality, in everyday behavior.

Hit is the correct detection of a signal that has been presented. Also, Hit is when a witness accurately identifies the person who committed a crime from a lineup

Hit rate is a term used in test-decision analysis that refers to the proportion of cases in which a test accurately predicts success or failure.

HIV RNA testing is the test that allows health care providers to monitor the amount of virus in the bloodstream.

HIV stands for a virus, the human immunodeficiency virus, which cripples the body's immune system. AIDS stands for acquired immunodeficiency syndrome. HIV is a sexually transmitted infection that can also be transmitted in other ways, such as sharing needles when shooting up drugs. AIDS is caused by HIV and describes the body's state when the immune system is weakened to the point where it is vulnerable to a variety of diseases that would otherwise be fought off .

- HMO (Health maintenance organization) : HMO (Health maintenance organization) refers to a managed care system that employs a restricted number of providers to serve enrollees. In an HMO, costs for all services are fixed. HMO is a managed health care organization. Please see Health maintenance organization (HMO)