Module 3-Slides

Question 1

Population
(Target Population)

Answer 1

ENTIRE group of interest to whom the study findings may be generalized

Question 2

Accessible Population

Answer 2

SUBSETS of the entire / target population who are AVAILABLE for researchers to study

Question 3

Sample

Answer 3

SUB-GROUP of the accessible population; serves as reference group to estimate characteristics of and draw conclusions
*Final Population being studied

Question 4

Inclusion Criteria for Selection

Answer 4

Primary traits of the target and accessible populations that will make someone ELIGIBLE to be a participant (characteristics of interest)

Question 5

Exclusion Criteria for Selection

Answer 5

Factors that would preclude someone from being a subject (INELIGIBLE)
EX: undesirable attributes - confounding factors/variables

Question 6

Confounding/ Extraneous Variables

Answer 6

VARIABLES that may CONFOUND the results or interfere with interpretation of the findings

Question 7

Probability Samples
(Selecting approach)

Answer 7

created via a process of RANDOM sampling or selection; to generate LESS BIASED AND CLOSER REPRESENTATIVE of the population

Question 8

Random sampling

Answer 8

equal chance/probability for all in population to be selected

Question 9

Nonprobability Samples
(Selecting approach)

Answer 9

made by non-random methods; more frequently used in CLINICAL STUDIES

Question 10

Types of Probability Sampling

Answer 10

1. Simple random
2. Systematic
3. Stratified random
4. Cluster
5. Disproportional

Question 11

Types of Nonprobability Sampling

Answer 11

1. Convenience
2. Purposive
3. Quota
4. Snowball

Question 12

Convenience Sampling

(nonprobability)

Answer 12

use of available participants
“accidental sampling”

MOST FREQUENTLY USED SAMPLING METHOD

Question 13

Purposive Sampling

(nonprobability)

Answer 13

used when specific expertise / experience of participants is needed

handpicked /invited bc of known characteristics

used in qualitative studies

Question 14

Quota Sampling

(nonprobability)

Answer 14

incorporate a stratification but lack of a randomization

subjects recruited to represent various levels/classes

Question 15

Snowball Sampling

(nonprobability)

Answer 15

used when it is difficult to find subjects

recruit via communication of “word-of-mouth”

usually when dealing with difficult/sensitive topics

Question 16

Examples of Convenience Sampling

Answer 16

Subjects found in a clinic
Volunteer subjects through ads/flyers

Question 17

Sample Size

Answer 17

Direct impact on validity of statistical conclusion; power analysis to determine the adequate sample size

Question 18

LARGER samples tend to be

Answer 18

MORE REPRESENTATIVE of the populations than smaller samples

Decrease sampling error

Question 19

Sampling Error

Answer 19

difference between an observed STATISTIC from a sample and the population PARAMETER

Question 20

Types of Clinical Trials

Answer 20

1. Therapeutic trials: effect of intervention
2. Diagnostic trials: accuracy of diagnostic procedures
3. Preventive trials: evaluation of whether a procedure or agent reduces risk of developing a disease or disorder

Question 21

Randomized Controlled Trials (RCTs)

Answer 21

Gold standard for experimental research

Random assignment

Two or more groups (experimental + control groups)

Measurements: Pre- / Post - interventions

Question 22

Assignment of Subjects / Participants

Answer 22

Can be done either NONRANDOMLY or RANDOMLY, determined by the purpose and nature of the study

-When COMPARING patients with age- and gender-matched healthy control subjects

Question 23

Balanced group

Answer 23

Achieved when there is NO LACK OF RANDOMIZATION

= # subjects/ = distribution of clinical/ + confounding characteristic

Question 24

Random assignment is preferred due to what?

Answer 24

validity issues

Question 25

Independent Variable (IV)

Answer 25

Intervention active variable can be MANIPULATED by researcher and assigned to levels of IV (=# of groups) Attribute variable cannot be manipulated (age/gender, disease duration/staging)

Question 26

Random Assignment

Answer 26

process of assigning subjects to groups (=chance of being assigned to any group) minimizes BIAS by creating groups that are similar at the start of trial

Question 27

Is random assignment the same as random selection?

Answer 27

NO

Question 28

Selection

Answer 28

process by which subjects are drawn or selected from the population RECRUITMENT/ENROLLMENT

Question 29

Assignment (or Allocation)

Answer 29

process by which subjects are placed into or allocated to a group within the study MANAGEMENT

Question 30

Random Assignment Strategies

Answer 30

1. Simple random 2. Block random 3. Stratified random 4. Cluster random 5. Random consent design 6. Assignment by patient preference 7. Run-in period

Question 31

Concealed Allocation (Assignment)

Answer 31

ensures group assignment is done w/out knowledge of those involved in the experimental process minimizes BIAS in group formation

Question 32

Control Groups

Answer 32

inactive controls: placebo, sham, attention control group wait list control: delayed start active controls: (practical, feasible /ethical reasons) -standard care or others with known efficacy

Question 33

Blinding (Masking)

Answer 33

minimizes observation BIAS by ensuring those involved in the study are unaware of a subject's group assignment -participant/subject/pt

Question 34

Double Blind

Answer 34

at least 2 of the 3 parties are unaware of group assignment

Question 35

Single Blind

Answer 35

at least 1 of the 3 parties is unaware of group assignment

Question 36

Explanatory Trial (RCT, aka True experimental)

Answer 36

ideal situations to control for confounding -strict and broad exclusion criteria -standardized treatment protocol

Question 37

Pragmatic Trial (RCT)

Answer 37

more reflective of practice situations -diverse pt populations w/fewer or min exclusion criteria -active controls (standard/other common care) -Tx reflects practice + less standardized

Question 38

Phases of Clinical Trials / New drug, surgical procedure

Answer 38

Phase I: Is the Tx safe? Phase II: Does the Tx work? Phase III: How does this Tx compare w/ standard care? Phase IV: What else do we need to know?