Chapter 12 Flashcards
An experimental study (intervention study) does what?
Assigns participants to intervention and control groups in order to test whether an intervention causes an intended outcome.
What is the primary distinction between an experimental study and other study designs?
Experimental studies assign participants to receive a particular exposure.
Which three studies are observational designs? (Dont “do” anything)
1) Cross-sectional
2) Case-control
3) Cohort
Which study is the gold standard for assessing causality?
Experimental study
A typical experimental study design in the health sciences is:
A Randomized Controlled Trial (RCT)
What is a randomized controlled trial (RCT)?
1) Some participants are randomly assigned to an active intervention group
2) The remaining participants are assigned to a control group
3) All participants from both groups are followed forward in time to see who has a favorable outcome and who does not.
What is a requirement of an experimental study?
The experiment has to be ethically justifiable.
What do you have to watch out for in experimental studies?
Noncompliance
What is the key statistical measure for experimental studies?
Efficacy
All experimental studies require careful definitions of:
1) The intervention
2) What type of control is appropriate
3) How participants will be assigned to exposure groups
4) What constitutes a favorable outcome for the trial
What is the first step in an experimental study?
Carefully defining the intervention that participants assigned to the active intervention group will receive, and deciding on the person, place, and time (PPT) criteria for the study.
What should the description of the experimental study state?
1) What the intervention will be
2) The eligibility criteria for participants
3) Where and how participants will receive the intervention
4) When, how often, and for what duration participants will receive the intervention 
What are the three types of experimental trials?
1) Superiority trial
2) Noninferiority trial
3) Equivalence trial
What is a superiority trial?
Demonstrates that a new intervention is better than the control. (Must define what “better” is)
What is a non-inferiority trial?
The intervention is not worse than the control.
What is an equivalence trial?
The intervention is equal to the control.
What is the first step for defining the measures of success?
Defining a favorable outcome for an individual.
What is one commonly used type of control group in experimental studies?
Placebo
What is a placebo?
An inactive comparison that is similar to the therapy being tested.
What is the goal of a placebo-controlled study?
It allows the effect of the active therapy to be examined separately from the boost in health status that people may experience simply by participating in a clinical trial or receiving some other intervention.
Do all experimental studies use placebos?
No; if the goal is to test whether a new therapy is better than the current one, we use the current therapy as the control.
Different interventions are compared in various combinations (ex. dosage and duration) within one randomized control trial using what kind of design?
Factorial design.
Why shouldn’t experimental studies include a control group of participants who are randomly assigned to maintain their usual routines?
1) Ethically: discourages the adoption of healthier lifestyles during the course of the study.
2) Hawthorne effect bias: participants change their behavior for the better because they know they are being observed.
Which study uses the same individuals as the control group?
A before-and-after experimental study.