An instructional manipulation check, often abbreviated IMC, is a special kind of question inserted in a

questionnaire A questionnaire is a research instrument that consists of a set of questions (or other types of prompts) for the purpose of gathering information from respondents through survey or statistical study. A research questionnaire is typically a mix of ...

among the regular questions, designed to check whether respondents are paying attention to the instructions. Discarding responses by participants who fail to read the instructions reduces the

signal-to-noise Signal-to-noise ratio (SNR or S/N) is a measure used in science and engineering that compares the level of a desired signal (electrical engineering), signal to the level of background Noise (signal processing), noise. SNR is defined as the ratio ...

ratio and can thereby increase the statistical power of an experiment. The tool was developed by Oppenheimer ''et al.'' Eliminating random responses this way before performing statistical hypothesis testing may be considered a legitimate form of

data manipulation Statistics, when used in a misleading fashion, can trick the casual observer into believing something other than what the data shows. That is, a misuse of statistics occurs when a statistical argument asserts a falsehood. In some cases, the misus ...

, but should be duly mentioned in publications reporting on the outcome of the experiment in question.

Blue-dot task

Among several forms an IMC can take, a popular one is the so-called blue-dot task, suitable for on-line questionnaires. A number of larger blue circles are arranged according to a Likert scale from (say) "very rarely" to "very frequently". Participants who ignore the instructions and merely want to finish the task will just click any one of these circles. The instructions, however, ask the participants to ignore the larger circles and instead click a little blue dot at the bottom of the screen. Oppenheimer ''et al.'' report that in a large sample of

undergraduate Undergraduate education is education conducted after secondary education and before postgraduate education. It typically includes all postsecondary programs up to the level of a bachelor's degree. For example, in the United States, an entry-le ...

participants, approximately 7% failed this task.

References

Questionnaire construction Survey methodology {{sci-stub