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Behavioral science 1
Question | Answer |
---|---|
the group being studied changes its behavior because they know they are being studied | hawthorne effect |
researcher's believe that a treatment is effective and it changes the outcome of the tx | pygmalion effect |
early detection is confused with increased survival. Seen with improved screening | lead time bias |
occurs when 2 closely associated factors "confound" each other | confounding bias |
subjects in different group are not treated the same | procedure bias |
the teacher pays special attention and spends mroe time with one gruop versus the other | procedure bias |
information is gathered at the wrong time i.e. using a survey to study a fatal disease | late look bias |
solution to late look bias | stratify by severity |
subjects are not representative of the general pupolation | sampling bias |
knowledge of presence of disorder alters recall by subjects | recall bias |
solution to recall bias | confirmation |
nonrandom assignment to study group | selection bias |
all sampling is from hospital pts | selection bias |
loss to follow up | selection bias |
ways to reduce bias | 1. blind studes 2. placebo responses 3. crossover studies (each subjects acts as own control to limit counfounding bias) 4. randomization to limit selection bias and confounding bias |
increase statistical power by? | meta analysis |
pools data and integrates results from several similar studies to reach a conclusion | meta analysis |
observer bias | the investicgator's decision is affected by prior knowledge of exposure status |