Non experimental designs

Question 1

name the 3 types of non experimental design

Answer 1

1) Descriptive correlational study
2) Case-control study
3) Cohort study

Question 2

what is cohort study?

Answer 2

It refers to ‘‘any
designated group of individuals who share
a common experience or condition”

It defines two or more groups of people that are free
of disease at the beginning but differ on their
exposure (e.g. smoking status) to a potential
causes of the diseases.

Question 3

what does cohort study investigate?

Answer 3

it investigates the etiology of disease based on one’s exposure to toxic/ carcinogenic substances.

Question 4

define exposed cohort

Answer 4

individuals experienced the
putative causal event or condition (i.e. smokers)

Question 5

define reference cohort

Answer 5

Reference cohort – individuals thought of
unexposed to the condition (i.e. non-smokers)

Question 6

what is the most straightforward type of epidemiologic study?

Answer 6

cohort study

Question 7

what is the primary goal of cohort study?

Answer 7

to measure and usually to
compare the incidence of disease or
event in the study cohorts.

Question 8

Name the 4 types of cohort studies:

Answer 8

1)prospective cohort
2)retrospective cohort
3)ambi-directional cohort
4) nested case control

Question 9

what is prospective cohort?

Answer 9

it is looking forward, likely to happen in the future.

defines a sample and predictor
variables before any outcomes (diseases)
have occurred and then collect the data for
the study in a prospective manner

Question 10

name 4 strengths of prospective study:

Answer 10

1) Able to control how to measure the exposure
2) Able to measure confounding variables
3) Avoid recall bias
4) Able to calculate relative risk for the outcome

Question 11

what are 2 weaknesses of cohort study?

Answer 11

1) costly
2) lengthy

Question 12

what is retrospective cohort?

Answer 12

it takes effect from the past.

defines a sample and predictor variables after
outcomes (diseases) have occurred. The
data basically exists and the investigators
use the data to answer the questions in
interest.

examples:
A retrospective cohort study on the risk of obesity among
shift workers

A retrospective cohort study of the Nagasaki atomic bomb
survivors for the risk of preleukemia.

Question 13

what are the 3 strengths of retrospective cohort study?

Answer 13

1) Inexpensive
2) Time-saving
3) Able to study longitudinally with long latent periods

Question 14

what are the 4 weaknesses of retrospective studies?

Answer 14

1) Risk of confounding variables - cannot measure as data has been collected

2) Sometimes unable to determine exact exposure
- unable to use an exact scale

3) Measurement error
4) Selection bias
- unable to control how participants of primary data were selected for inclusion

Question 15

what is ambi directional cohort?

Answer 15

combination of retrospective and prospective to gain more information to help answer the question.

Question 16

1 Strength for Ambi-directional cohort study

Answer 16

Captures exposures that can cause both short-term &
long-term outcomes

Question 17

3 Weaknesses of ambi-directional cohort study

Answer 17

1) Costly and lengthy
2) Risk of confounding variables
3) Exposure determination problems

Question 18

define risk for cohort study analysis

Answer 18

Risk is defined as the probability that an event occur and
it is measured as incidence rate (IR) in cohort study

Question 19

What is rate ratio/ risk ratio/ relative risk.

Answer 19

Define as the
ratio between the incidence rates of the two groups,
can be used to compare the risk in the two groups:
RR=IR E /IRNE

Question 20

what is the purpose of descriptive study?

Answer 20

To observe, describe and document aspects of a
situation

Question 21

what is the purpose of descriptive correlational study

Answer 21

To examine a relation between variables without
attempting to infer causal relationship

Question 22

what are the 5 methods of analysis for simple descriptive study?

Answer 22

Descriptive statistics like
mean,
standard deviation,
median,
frequency,
percentage, etc.

Question 23

what are the 4 methods of analysis for descriptive correlational study?

Answer 23

Descriptive correlational study –
Pearson’s
correlation,
Spearman’s rank correlation,
regression,
logistic regression, etc.