EXITS Flashcards
External validity
External validity is the extent the results can be generalized to the target population or clinical settings
Internal validity
Internal validity is the extent conclusions from the studies can be made, based on the studies design settings and measures.
Construct Validity
The extent to which a test measures the theoretical construct the test is supposed to measure.
Content Validity
The extent to which a test fully measures all the domains of the construct of interest.
Criterion Validity
That determines the relationship of the scores on a test to a specific criterion, which is usually another validated test
Inter-rater Reliability
The extent results are consistent among different raters who are rating the same information.
How to measure inter-rater reliability
Cohen Kappa coefficient (for categorical items) Intraclass correlation coefficient (for continuous items) 0.2-0.4=slight to fair 0.4-0.6=moderate 0.6-0.8= substantial >0.8=almost perfect
Test-retest Reliability
The extent results are consistent when the test is conducted at two different times with no intervention in between.
Bias
Systematic error that arises from the from the design, conduct and analysis of a study, resulting in observed result which deviate from the truth.
What are the common selection bias for case control study
referral, non-responder, volunteer bias, incidence prevalence bias
What is Hawthorne effect
The Hawthorne effect refers to the increase in performance of individuals who are noticed, watched, and paid attention to by researchers or supervisors
What is Case Control study
Type of analytical observation study used to investigate the relationship between risk factor and outcome
The study is created by having a group of subject with the outcome and matched with a group without the outcome and the differences in previous exposure to risk factors were being investigated.
(3)Pros and (4)cons of case control study
pros: efficient, useful to study rare disease/outcome, use to study a wide range of exposure
Cans: RECALL BIAS, cannot estimate prevalence or incidence, temporal relationship can be uncertain, not efficient for rare exposure, relative risk is measured indirectly (since we cannot estimate prevalence)
Cohort study
is a form of longitudinal study that samples a group sharing a exposure to match a group that is not exposed to a risk factor. Both groups are followed up to investigate the diff likelihood of the outcome on the two groups
Pros and cons of cohort study
Pros
no selection bias
Well suited for rare exposure
Can study multiple diseases from a single exposure
Cons
Very expensive, Long time to complete, if prospective will have loss of followup
Randomised controlled trial
An intervention study in which a group of subjects with similar characteristics are randomised to received one of the several defined intervention
Factorial trial
Studying more than 1 intervention and also the effect of their interactions
Cross over trial
Study where each subject received two or more study treatment in a specific order. Each subject become his own control
Systematic Review
A type of comprehensive literature review which assess and review all the pertinent articles in the field using explicit criteria and pool the results together to answer a clinical question
Meta analysis
Quantitative assessment of a systemic review
Which involves pooling the results of independent studies together to produce an overall estimate of effect
Confidence Interval
A range of values within which the true value lies with a certain level of assurance.
Standard Error
Standard error is used to calculate the confidence interval of the result.
Standard deviation over square root sample size
Alpha level
Is the threshold at which we will accept or reject the null hypothesis.
Typically sets at 5%.
A alpha level of 5% means that the observed results had occurred by chance at most 5% of the time.
P value
It represents the likelihood the observed result has occurred by chance.