Threats to Internal Validity

a general approach to research that involves measuring a variable or set of variables as they exist naturally to produce a description of individual variables as they exist within a specific group, but does not attempt to describe or explain relationships between variables

shows the changing values of two variables, a pattern in which the data points tend to cluster around a straight line

graph showing the changing values of two variables, a pattern in which the data points tend to cluster around a curved line

a relationship in which the two variables or measurements tend to change together in the same direction

a relationship in which the two variables or measurements tend to change together in opposite directions

General approach to research that involves measuring two or more variables for each individual to describe the relationship between the variables

Research strategy that attempts to establish the existence of a cause- and-effect relationship between two variables by manipulating one variable while measuring the second variable and controlling all other variables

a strategy that attempts to limit threats to internal validity and produces cause and effect conclusions but lacks either manipulation or control

a strategy that attempts to demonstrate a relationship between two variables by comparing different groups of scores but makes no attempt to minimize threats to internal validity or to explain the relationship

specifies whether the study will involve groups or individual participants, will make comparisons within a group or between groups, and how many variables will be included in the study

is an exact, step-by-step description of a specific research study

refers to the extent to which we can generalize the results of a research study to people, settings, times, measures, and characteristics other than those used in that study

produces a single, unambiguous explanation for the relationship between two variables

Threats to External Validity: Category 1

Threats to External Validity: Category 2

Threats to External Validity: Category 3

any variable in a research study other than the specific variables being studied

is an extraneous variable (usually unmonitored) that changes systematically along with the two variables being studied. provides an alternative explanation for the results

Threats to Internal Validity

occurs when the experimenter's expectation or personal beliefs regarding the outcome of the study influence the findings of a study.