EBP Midterm - Critically Appraising RTC's

RTC’s identify _______ and ________

cause, effect

RTC’s use comparison statistics such as _____ and _____- to identify relationships

ANOVA, t-tests

RCTs meet 3 requisite design characteristics:

manipulation of independent variables, random assignment, use of a control group

Define Efficacy (ideal world)

what could happen in the best possible environment.

Define Effectiveness (real world)

what is likely to happen as a result of treatment in typical clinical environments.

A RCT is an _______ trial

efficacy

A Pragmatic clinical trial (PCT) is an ________ trial

effectiveness

You need to be able to answer these three questions about an RCT article:

are the design and results valid, are the results meaningful, are the results relevant to my clinical question

Experimental areas that asses Internal Validity (5)

randomization, bias, blinding, funding, author conflict

the goal of any research study is to find _________.

truth

Types of bias: Selection /Sampling

distorts treatment effects because of the way comparison groups are formed

Types of bias: Performance bias

difference in care provision to the experimental and control groups

Types of bias: Attrition

differential loss of subjects across comparison groups

Types of bias: Detection bias

if outcome assessment differs across comparison groups

Define prospective study

designed before the patients receive treatment (less biased)

Define retrospective study

designed after the patients receive treatment (chart review, higher bias)

4 sources of measurement bias

subject and observer variation, deficiency of tools, technical error in measurement

Define Intention-to-treat (ITT) principle requirement

80% of participants stay in their original assignments for results to remain valid

If CIs overlap there may be ____________ difference between groups

no significant

If CIs don’t overlap there may be ____________ difference between groups

significant

If CIs includes 0 there may be ____________ difference between groups

no significant

Define Effect size (Cohen’s d)

measures the magnitude of the difference between groups

Cohen’s d Value: Large =

>0.8 (significant difference)

Cohen’s d Value: Medium =

0.5-0.8

Cohen’s d Value: Small =

0.2-0.5

Define number needed to treat

ratio of the rate of the desired outcome in the
experimental group and the rate of the desired outcome in the
control or comparison group

What is the ideal number needed to treat?

1 (but 2-3 indicates good therapy)