Glossary

Research carried out for practical applications and problem-solving functions.

An attitude measurement survey is a study, on a properly drawn sample, of a specified population to find out what people in that population feel about a specified issue.

Research carried out to discover something simply for the sake of knowledge to improve our
understanding of the world, and for academic rather than commercial purposes.

variables that take on values that are names or labels

Research that is used to educate policymakers and stakeholders on social issues and propose possible solutions.

A type of Criterion validity. Examines how well a tool provides the same scores as an already existing tool.

seeks an agreement between a theoretical concept and a specific measuring device, such as observation.

re not observable but can be defined based on observable characteristics

The extent to which a measure “covers” the construct of interest, i.e., it's comprehensiveness to measure the construct.

a group in a randomized experiment that receives an inactive treatment but is otherwise managed exactly as the other groups

A variable that theoretically should be correlated with the construct being measured (plural: criteria).

The extent to which people’s scores on a measure are correlated with other variables (known as criteria) that one would expect them to be correlated with.

a set of observations (a set of possible outcomes); most data can be put into two groups: qualitative (an attribute whose value is indicated by a label) or quantitative (an attribute whose value is indicated by a number). Quantitative data can be separated into two subgroups: discrete and continuous. Data is discrete if it is the result of counting (such as the number of students of a given ethnic group in a class or the number of books on a shelf). Data is continuous if it is the result of measuring (such as distance traveled or weight of luggage)

research that describes or defines a particular phenomenon

The process of developing systematized knowledge gained from observations that are formulated to support insights and generalizations about the phenomena being researched.

research that evaluates the outcomes of a policy or program

an operation or procedure carried out under controlled conditions in order to discover an unknown effect or law, to test or establish a hypothesis, or to illustrate a known law.

any individual or object to be measured

the independent variable in an experiment; the value controlled by researchers

Conducted during the early stages of a project, usually when a researcher wants to test the feasibility of conducting a more extensive study or if the topic has not been studied in the past

This is a synonymous term for generalizability - the ability to apply the findings of a study beyond the sample to a broader population.

The extent to which a measurement method appears “on its face” to measure the construct of interest

a research tradition involving interview data collected in a group setting (rather than from individual participants).

the number of times a value of the data occurs

the variable in a study design presumed or hypothesized to vary on its own, but that determines variation observed in the dependent (outcome or output) variable; the “input” variable in a study design (i.e., usually denoted as the “x” variable, where “y” denotes the dependent variable).

A variable constructed from an original set of variables to try to represent either all of the interaction present or some part of it.

the extent to which all questions or items assess the same characteristic, skill, or quality.

Ability to say that one variable "causes" something to happen to another variable. Very important to assess when thinking about studies that examine causation such as experimental or quasi-experimental designs.

A higher level of measurement. Denoted by having mutually exclusive categories, a hierarchy (order), and equal spacing between values. This last item means that values may be added, subtracted, divided, and multiplied.

a variable not directly observed but mathematically or statistically inferred from other variables that are directly measured.

study design where data are collected repeatedly from the same individuals/elements/units over time.

The process by which we describe and ascribe meaning to the key facts, concepts, or other phenomena that we are investigating.

regression model used to find an equation that best predicts the YYvariable as a linear function of multiple XX variables

level of measurement that is categorical and those categories cannot be mathematically ranked, though they are exhaustive and mutually exclusive

another name for categorical variables (categories have names, are not numeric)

A hypothesis set up to be refuted in order to support an alternative hypothesis; presumed true until statistical evidence in the form of a hypothesis test indicates otherwise.

Level of measurement that follows nominal level. Has mutually exclusive categories and a hierarchy (order).

categories of a variable have numeric relationships, can be sequenced in numeric order but are not continuous interval variables (for example, ratings of frequency from never to always)

a number that is used to represent a population characteristic and that generally cannot be determined easily

a value indicating the effect of each independent variable on the dependent variable with the influence of all the remaining variables held constant. Each coefficient is the slope between the dependent variable and each of the independent variables

a higher order form of linear regression in which the relationship between the independent variable xxand the dependent variable yy is modeled as an nnth order polynomial

all individuals, objects, or measurements whose properties are being studied

A type of criterion validity that examines how well your tool predicts a future criterion.

data collected with the intention of meeting aims of the specific research study for which the data are collected.

a number between zero and one, inclusive, that gives the likelihood that a specific event will occur

selecting research participants using methods that ensure every member of the original population has an equal chance (probability) of being selected; (see random selection).

the number of successes divided by the total number in the sample

Empirical research in which the researcher explores relationships using textual, rather than quantitative data. Case study, observation, and ethnography are considered forms of qualitative research. Results are not usually considered generalizable, but are often transferable.

Also known as categorical variable has no natural sense of ordering; takes on names or labels.

Empirical research in which the researcher explores relationships using numeric data. Survey is generally considered a form of quantitative research. Results can often be generalized, though this is not always the case.

a subtype of experimental design that is similar to a true experiment, but does not have randomly assigned control and treatment groups

the act of organizing experimental units into treatment groups using random methods

Errors lack any perceptable pattern.

The highest level of measurement. Denoted by mutually exclusive categories, a hierarchy (order), values can be added, subtracted, multiplied, and divided, and the presence of an absolute zero.

The ability of a measurement tool to measure a phenomenon the same way, time after time. Note: Reliability does not imply validity.

a subset of the population studied

a composite measure designed in a way that accounts for the possibility that different items on an index may vary in intensity (5.3)

research using data originally collected for a different research purpose (a secondary use of the data).

a numerical characteristic of the sample; a statistic estimates the corresponding population parameter.

a description of a phenomenon using probability distributions that describe the expected behavior of the phenomenon and the variability in the expected observations.

a study in which data is collected as reported by individuals.

Errors that are generally predictable.

The extent to which the scores from a measure represent the variable they are intended to.

refers to a grouping of several characteristics