In previous chapters, nuisance variables and the biases they may bring about were discussed. It is vital to the study that such bias is avoided. This chapter provides an overview of several countermeasures that can be taken. This section discusses errors that can be avoided after which the study designs are greatly improved, often without increasing the cost or time it takes to complete the studies.
Subject-related bias, where the subjects’ behavior is different from what could be expected in normal circumstances, can be countered in many ways, ranging from increasing the neutrality of the location to conducting a single-blind study where subjects do not know to which experimental condition they are assigned. Experimenter-related bias, where the experimenter unintentionally influences the study results or the subjects, can be countered with measures ranging from standardized instructions and behaviors to using a double-blind approach where both subjects and experimenter do not know to which experimental condition the subject is assigned.
KeywordsContinuous Positive Airway Pressure Carryover Effect Sleep Apnea Patient Nuisance Variable Diabetes Treatment Satisfaction Questionnaire
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