or unintentional). An example of this is provided in Stephen Jay Gould's 1981 book "The Mismeasure of Man". Among the questions used around the time of World War I in the battery used to measure intelligence was "In which city do the Dodgers play?" (they were then based in Brooklyn). Recent immigrants to the US from Eastern Europe unfamiliar with the sport of baseball got the answer wrong, and this was used to infer that Eastern Europeans had lower intelligence. The question did not measure intelligence: it only measured how long one had lived in the US and become accultured to a popular pastime. Researcher expectations may be communicated unintentionally to the participants non-verbally, eliciting the desired effect. To control for this possibility, double-blind experimental designs should be used where possible. That is, the evaluator of a particular participant should be unaware of what intervention has been performed on that particular participant or should be independent of the experimenter. Defining predicted outcome too narrowly. For instance, using only job satisfaction to measure happiness will exclude relevant information from outside the workplace. Confounding variables (covariates): The root cause for the observed effects may be due to variables that have not been considered or measured. An in-depth exploration of the threats to construct validity is presented in Trochim. See also Statistical conclusion validity Internal validity Ecological validity Content validity External validity Reliability (psychometrics) Face validity Logical validity Jingle-jangle fallacies Lee J. Cronbach Paul E. Meehl References External links Useful reference guide for research terms Provides a visual representation of the nomological network