V

Validity
The extent to which a measurement instrument or test accurately measures what it is supposed to measure. FOR EXAMPLE, a reading test is a valid measure of reading skills, but it is not a valid measure of total language competency.

Validity Assessment
The procedures necessary to demonstrate that a question or questions are measuring the concepts that they were designed to measure.

Variable
Variables can be classified into three categories:

Independent (input, manipulated, treatment, or stimulus) variables, so called because they are "independent" of the outcome; instead, they are presumed to cause, effect, or influence the outcome.
Dependent (output, outcome, response) variables, so called because they are "dependent" on the independent variable; the outcome presumably depends on how these input variables are managed or manipulated.
Control (background, classificatory, or organismic) variables, so called because they need to be controlled, held constant, or randomized so that their effects are neutralized, canceled out, or equated for all conditions. Typically included are such factors as age, sex, IQ, SES (socioeconomic status), educational level, and motivational level; it is often possible to redefine these particular examples as either independent or dependent variables, according to the intent of the research.

A fourth category having to do with conceptual states within the organism is often cited: intervening variables (higher order constructs). These cannot be directly observed or measured and are hypothetical conceptions intended to explain processes between the stimulus and the response. Such concepts as learning, intelligence, perception, motivation, need, self, personality trait, and feeling illustrate this category.

Variance
A measure of the spread of the values in a distribution. The larger the variance, the larger the distance of the individual cases from the group mean.

Verification
An effort to test the accuracy of the questionnaire response data. The concern is uniquely with data accuracy and deals with neither the reliability nor the validity of measures.

Victimization Information
Data collected from the victims of crime concerning offenses of which they were the victims, offender characteristics, and/or victim characteristics.

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