To determine if research results are valid and relevant, what three things must you know about the study?
study design, measurement methods, and control bias
How many levels of evidence are there?
What is the highest level of evidence? It offers the most reliable and valid evidence.
a well designed meta-analysis of more than one randomized control trial (RCT)
What is the second level of evidence?
well-designed controlled study without randomization (cohort design or quasi-experimental studies)
What is the third level of evidence?
well-designed non-experimental studies (correlation and single person studies)
What is the fourth level of evidence? This is the least effective evidence.
expert committee reports, consensus statements, clinical experience, or respected authorities
What is the gold standard design for a study?
randomized control trial
What is a randomized control trial?
will have an experimental and control group that is randomly assigned
What is a cohort study design?
may have experimental and control groups but lacks randomization
What is a single case study design?
follows one subject across time to evaluate treatment method
How might results of a study be reported?
in terms of statistical significance
What is the usual criterion for a study? What does that mean?
p<.05, probability is less than 5% that an observed difference might have happened by chance
What is sample (subject selection) bias?
subjects in the sample aren't representative of the population to be studied
What is measurement bias?
too few or too many tools being used to measure the outcomes
What is intervention (performance) bias?
may be caused by treatment bias, timing of intervention, treatment site, use of different therapists
What four questions do you want to consider when looking at a research study?
were there statistically significant differences between experimental and control group, were the outcome measures valid and reliable, were participants randomly assigned, and were evaluators blinded to group assignments