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Definition
| Whatever alternative to the null hypothesis is being considered (e.g. null hypothesis) |
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| loss of units; in randomized experiments, refers to loss that occurs after random assignment has taken place (aka mortality) |
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| A purposive sample whose mean on a characteristic matches the population mean for that characteristic |
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| Between participants design |
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| Different units are studied in different conditions |
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| Systematic error in an estimate or an interference |
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| The process of dividing units into groups with similar scores on a blocking variable, each group having the same number of units as the number of conditions |
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| The effects of one treatment do not end prior to the administration of a second treatment. so that the effects observed in teh second treatment include residual effects from the first |
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| A study tht contrasts units with an outcome of interest to those without the outcome to identify retrospectively the predictors or causes of the outcome (aka case-referent study) |
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| Identifying that a causal relationship exists between A and B |
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| Explaining how A causes B |
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| Inferences that describe how well a causal relationship extends across or beyond the condtions that were studied |
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| A model of causal relationships, usually with mediators; sometimes refers to efforts to identify causes and effects in nonexperimental studies |
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| A variable that produces an effect or result |
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| Responses on a vraible closely approach the maximum possible response so that further increases are difficult to obtain |
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Definition
| In an experiment, a group that is compared with a treatment group and that may receive either an alternate intervention or no intervention |
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| A path consisting of two or more direct paths connected together |
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| The strategy of showing that a hypothesis is correct or is supported by evidence |
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| An extraneous variable that covaries with teh variable of interest |
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Definition
| a concept, model or schematic idea |
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| the degree to which inferences are warranted from the observed persons, settings, and cause and effect operations sampled with a study to constructs that these samples represent |
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| A measure of the strength of relationship between two variables |
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| A study that observes relationships between variables |
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| In within-participants designs, arranging the order of condistions to vary over units so that some units are given Treatment A first but others are given Treatment B first |
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| Designs in which all units are exposed to all conditions |
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| Often synonynous with effect or outcome, a variable with a value that varies in response to teh independent variable |
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Definition
| Something an experimenter can manipulate or control in an experiment to help address a threat to validity |
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Definition
| The notion that a measure of A can be discriminated from a measure of B, when B is thought to be different from A; discriminat validity correlations hould be lower than convergent valdity correlations |
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Definition
| a study that breaks down a treatment into its componet parts to test teh effectiveness of the parts |
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Definition
| An experiemtn in whcih both teh treatment provider and treatment recipient are unaware of which treatment or control conditions is being administered, primarily used in medical clinical trials |
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Definition
| A measure of the magnitude of a relationship, specific instances of which include the standardized mean difference statistic, the odds ration, teh correlation coedfficient, the rate difference and the rate ratio |
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Definition
| How well an intervention works when it is implemented under conditions of actual application |
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| How well an intervention works when implemented under ideal conditions |
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| A variable that is caused by otehr variables within the model |
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| a varaible that is not casued by otehr varibales in teh model |
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| the mean of a statistic based on repeated samplings |
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Definition
| To explore the effects of manipulating a variable |
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Definition
| the validity of inferences about whether the causal relationship hold over variations in persons, settings, treatment variables, and measurement variables |
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Definition
| To show that data are inconsistent with a theory of hypothesis |
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Definition
| Participants tire over time, causing performance to deteriorate in later conditions or later assessments |
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Definition
| The capacity of a method to provide precise answers about a narrow questions, often at the cost of high bandwidth |
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Definition
| The hypothesis that studies that were rejected because of reviewer prejudice against null findings are never published and so remain unavailable to future literature reviews, resulting in a systematic bias in teh results of the review |
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Definition
| Response on a variable approach the minimum possible score so that further decreases are difficult to obtain |
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| The characteristics of the true relationship among variables, represented graphically bu teh shape of the relationship and represented statistcally by a model taht may includ enonlinear terms or other transformation |
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Definition
| Unobserved variables that may cause bias in treatment effect estimates |
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Definition
| The activities, both intended and unintended, that did and did not occur as part of the treatment conditions |
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Definition
| Often synonymous with cause or treatment, a variable that purports to be independent of otehr influences. Some authors advocate a more limited usage whereby a variable is independent only if the mehtodology isolates teh variable from otehr influences |
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Definition
| A path between two varaibles that requires going through a third variable to make the connection |
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Definition
| The process of giving research participants the information they need to make an informed choice about whether participate in a study given its risks and benefits |
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Definition
| A variable or set of variables(or more generally an estimateation technique) that is correlated with outcome only through an effect on other variables |
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Definition
| An analysis of a randomized experiment in whcih units are analyzed in the condition to which tehy were assigned, regardless of whether they actually recieved the treatment in that condition |
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Definition
| In experiments, when the effects of treatment vary over levels of another variable |
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Definition
| The validity of inferences about whether the relationship between two varaibles in causal |
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Definition
| A variable that is not directly observed but is inferred or estimated from observed variables |
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Definition
| Sometimes synonymoous with blocking, sometimes more specific to imply blocks in which units are exactly equal (rather than just similar) on matching variable |
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Definition
| Failure to obtain measures on units (whether or no they are treated) |
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Definition
| A third variable that comes between a casue and effect and that transmits the causal influence from the cause to the effect |
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Definition
| A set of quantitative methods for synthesizing research studies on the same topic (research synthesis) |
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Definition
| In an experiment, a variable that influences the effects of treatment |
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Definition
| Investigates the effects of a naturally occurring event, sometimes limited to events that are not mainpulable, such as earthquakes, and sometimes used more generally |
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Definition
| Designs in which units are exposed to some but not all conditions |
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Definition
| When some units are grouped together into aggregate units, units are said to be nested within aggregates |
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Term
| Nonequivalent dependent variable |
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Definition
| A dependent variable that is predicted not to change because of the treamtne byt is expected to respond to some or all of the contextually important internal validit threats in teh same way as the target outcome |
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Definition
| Any study that is not an experiment |
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Definition
| In teh structural equation modeling literature, a mdoel that allows recirpocal causation, although some literatures use the term differently |
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Definition
| The hypothesis being tested, traditionally that there is no relationship between variables |
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| Null Hypothesis Significant Testing |
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Definition
| The practice of testing the hypothesis that there is no effect and then declaring that an effect exists only if p <.05 |
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Definition
| A study in which variables are observed rather than manipulated; used in some literatures to include quasi-experiments |
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Definition
| a variable that is directly measured in a study |
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Definition
| variables that are not in a model or an alaysis that influence both the cause and the effect and so may cause bias |
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Definition
| usually synonymous with operations but sometimes used in a restricted sense to imply the methods used to present a construct |
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Definition
| the actions actually doen in a study to present units, treatments, observations, settings and times |
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Definition
| The outcome of a study is affected by the order in which the treatments were presented |
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Definition
| a form of observation inwhich the researcher takes on an established participant role in the contest being studied |
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Definition
| a measure of the strength of relationship between two variables connected by a direct path |
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Definition
| the general concept of matching a pattern of evidence to pattern predicted by theory or past research |
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Definition
| An intervention that does not include the presumed active ingredients of treatment |
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Definition
| the probability of correctly rejecting a false null hypothesis; in an experiment, usually interpreted as the probability of finding an effect when an effect exists |
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Definition
| Participants become better at something the more often tehy do it, a potential problem in within-participants designs in which repeated tests are given to the same participants |
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Definition
| An experiment, any procedure for assigning units to conditions based on chance, with every unit having a nonzero probability of being assigned to each condition |
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Term
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Definition
| In an experiment, any procedure for assigning units to condtions based on chance, with every unit having a nonzero probability of being assigned to each condition |
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Definition
| Any procedure for selecting a sample of units from alarger group based on chance, frequently used in survey research to facilitate generalization from sample to population |
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Definition
| More general term that is sometimes used synonymously with eitehr random sampling or random assignment in different contexts |
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Definition
| experiment in which units are randomly assigned to conditions |
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Definition
| Reanalysis of prmary study data after the study is completed usually donen by someone other than the original aurthors |
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Definition
| The process by which units are assigned to conditions/ a threat to internal validity in which systemataic differences over conditions in repondent characteristics could also causes the observed effect |
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Definition
| When selection results in dfferences in unit characteristics between conditions that ma be related to outcome differences |
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Definition
| when units decide the condition they will enter |
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Definition
| random assignment with equal probability of assignment to each condition without use of ancillary methods such as blocking, matching or stratification |
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Definition
| a time series done on one person, common in clinical research |
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| Statistical conclusion validity |
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Definition
| the validity of inferences about the covariation between two variables |
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Definition
| the process of creating homogeneous groups of units in which each group has more units than there are experimental conditions |
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Definition
| effects due to repated testing of participants over time |
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Definition
| reasons why an inference might be incorrect |
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Definition
| whether the participant uses the treatment as instructed |
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Definition
| failure of units to receive treatment |
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Definition
| Whether the treatment is provided by the experimenter to the participant |
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Definition
| in an experiment, the group that receives the intervention of interest |
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Definition
| whether the participant actually receives the treatment that was provided |
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Definition
| incorrectly rejecting the null hypothesis/ concluding there is an effect when really there isn't |
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Definition
| failing to reject a false null hypothesis/ concluding there isn't an effect when there is one |
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Definition
| an opportunity to apply or withhold treatment |
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Definition
| units are nested within aggregates in a way that may violate the independence assumption of many statistics |
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Definition
| the truth of, correctness of or degree of support for an inference |
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| within participants design |
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Definition
| the same units are studied in different conditions |
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Definition
| degree to which two measures of constructs that theoretically should be related, are in fact related |
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Definition
| error in a statistical analysis arising from the unrepresentativeness of the sample taken. |
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