epi

Question 1

Statistical Associations

Answer 1

generally, positive findings of epidemiologic or clinical outcome studies

Question 2

Perfect Linear relationship

Answer 2

For every unit of increase in one variable, the other variable increases
or decreases proportionally & Coefficient, represented by r

Question 3

Intra-class correlation

Answer 3

Looks at the agreement of measurements within classes or categories & Is
a useful measure of validity, reliability, or inter-rater agreement

Question 4

The fewer the subjects, the more likely results may be influenced by

Answer 4

chance sampling variation

Question 5

selection bias

Answer 5

study subjects are selected in a way that can increase or decrease magnitude of an
association—misleadingly

Question 6

Information bias

Answer 6

when the method of data collection makes the information obtained from two or
more groups differ in some misleading way. Result in misclassification of subjects with respect to
disease or possible causal factors

Question 7

specification

Answer 7

simplest method for controlling variables in the data analysis & data from each

Question 8

Sensitivity deals with

Answer 8

true positives

Question 9

specificity deals with

Answer 9

false positives

Question 10

If the query is new and there is not much information on what is to be investigated, you should
start with a

Answer 10

case study, if it doesn’t, next step would be look at case series

Question 11

Quasi-experimental Designs have many features of an RCT, but

Answer 11

generally are not double blinded

and if single group, there is no randomization

Question 12

RCT

Answer 12

Should be randomized, blinded (2 way preferred), no other bias in structure or in execution
of trial, and appropriate analysis

Question 13

Journal editors must be more cautious about making sure that

Answer 13

replication—an essential issue in

research reliability—can be done

Question 14

Credit for the modern randomized trial is usually given to

Answer 14

Sir Austin Bradford Hill

Question 15

RCT are not appropriate for

Answer 15

cancer screening

Question 16

Efficacy refers to

Answer 16

an RCT or 2 group or more trial of some other type; maintain research rigor here

Question 17

Effectiveness

Answer 17

refers to a single group trial where pre and post intervention is evaluated; similar to
daily practice

Question 18

phase 1

Answer 18

are usually conducted after the safety of the new intervention has been
documented in animal research, and their purpose is to document the safety of the intervention in
humans – usually case series or outcome studies

Question 19

phase 2

Answer 19

the intervention is given to a small group of real patients, and the purpose of this study is
to evaluate the efficacy of different modes of administration of the intervention to patients – focus on efficacy while still providing information on safety

Question 20

phase 3

Answer 20

Performed after a given procedure has been shown to be safe with a reasonable chance of improving patients’ conditions. Most phase 3 trials are randomized controlled trials - Here the study would be looking at two or more groups with persons assigned to different interventions/placebo

Question 21

phase 4

Answer 21

Studies are equivalent to post-marketing studies of the intervention; they are performed to identify and monitor possible adverse events not yet documented - Earlier studies, even RCTs, do not give an opportunity to discover whether a product will produce a side effect in someone with an esoteric condition. This phase is quite important

Question 22

parallel design

Answer 22

Most randomized controlled trials have parallel designs in which each group of participants is exposed to only one of the study interventions

Question 23

crossover design

Answer 23

crossover design refers to a study in which each of the participants is given all of the study interventions in successive periods. The order in which the participants receive each of the study interventions is determined at random

Question 24

factorial design

Answer 24

A randomized controlled trial has a factorial design when two or more experimental interventions are not only evaluated separately but also against each other and against a control - A 2 × 2 factorial design generates four sets of data to analyze: data on patients who received none of the interventions, patients who received treatment A, patients who received treatment B, and patients who received both A and B

Question 25

sequential trial

Answer 25

A sequential trial is a study with parallel design in which the number of participants is not specified by the investigators beforehand. Instead, the investigators continue recruiting participants until a clear benefit of one of the interventions is observed or until they become convinced that there are no important differences between the interventions

Question 26

fixed trials

Answer 26

Alternatively, in a fixed trial, the investigators establish deductively the number of participants (sample size) that will be studied. This number can be decided arbitrarily or can be calculated using statistical methods. The latter is a more commonly used method.

Question 27

statistical correction (intent to treat)

Answer 27

A method to correct for differential dropout rates between patients from one arm of the study and another is to analyze data by the intent to treat—that is, data are analyzed in the way patients were randomized, regardless of whether or not they received the intended intervention. The intent to treat correction is a form of protection against bias and is believed to strengthen the conclusions of a study