Week 8 - Quantitative

Front 1

Research Designs

Back 1

- Framework that directs research process (who, what, when, where, why)
- In "method" section
- Purpose: answer research q's

Front 2

Good research designs - OFACIE

Back 2

- Objective : Lit review reflects who, what, when, where, why
-Accurate : Answers research question accurately
- Feasible : Follow large enough sample size to answer q within time & $$
- Control : Able to control sources of bias to give valid results
- Internal validity : results = believable
- External validity : results = useful for other people/situations

Front 3

Validity

Back 3

- Correct / accurate
- ie mass measuring instrument reads 55kg for an object thats 55kg
- ie BP cuff is valid to measure BP, thermometer is not valid to measure BP

Front 4

Reliability

Back 4

- Consistency
- ie mass measuring instrument measures same everytime
- ie BP cuff should be properly calibrated to measure BP reliably

Front 5

Types of validity measures

Back 5

Internal Validity
- Are changes in outcome (DV) DUE to changes in exposure (IV)?
- Goal = rule out other explanations
External Validity
- Can findings be generalized to other pops/settings?
- goal = useful beyond participants, replication

Front 6

Threats to internal validity

Back 6

- Selection bias : If participant's characteristics raise possible alternate explanation
- Instrumentation: Inter rater differences, failure of instrument
- History: If event occurs simultaneously with intervention that affects outxome (celebrity death example)
- Maturation: external, innate changes to participant unrelated to study (ie disease progression)
- Testing : Act of being tested once affects outcome of next test through memory (think alzheimer's pt's)
- Mortality/attrition : Loss of participants over time

Front 7

Threats to External validity

Back 7

Selection Effects:
- Study sample doesn't represent population of interest (ie Dad's at Justin Bieber concert)
- Hawthorne/Observer effect : Subjects improve/modify behaviour when they know they're watched
Reactivity:
- Natural reactions to being studied
Measurement Effects:
- Actual act of being tested affects outcome

Front 8

Experimental (RCT)

Back 8

- Participants randomly assigned to experimental or control group, randomized control trial
- Gold standard, control most threats
- Strengths: control, participants blinded, establishes causality / causal direction, double blinding possible (not always ethical
- Weakness : difficult to implement, generalizability can be low, sometimes not ethical

Front 9

Experimental --> After only

Back 9

- Used for studies where there's no pre, ie surgery post op pain

Front 10

If you delete initial randomization step from experimental design...

Back 10

Quasi experimental design: Non - Equivalent Control

Front 11

If you delete control group entirely...

Back 11

Quasi experimental design: One group (pre-test post-test)

Front 12

Quasi - Experimental

Back 12

- Participants not randomly assigned, but there is a control group (think smoking, if you smoke or if you don't smoke determines the group you're in, it's not random, but theres still a control group)
- Control some threats
- Strengths: Establish causality / causal direction, control
- Weakness: Not clear cause + effect, may be difficult to implement, generalizability low, not always ethical
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Front 13

Quasi - Time Series

Back 13

- Number of pre tests, number of post tests

Front 14

Non Experimental

Back 14

- No control group / experimental group comparison
- Control some threats, no manipulation of variable no randomization

Front 15

Non experimental - cross sectional

Back 15

Strengths: Fast, heap, large # of participants / variables
Weakness: No causal association, threats to validity (many bias)

Front 16

Non experimental - Prospective (longitudinal cohort)

Back 16

- Strengths: Time line established (exposure before outcome), large # of participants / variables
- Limits: VERY expensive (due to long term follow ups), large attrition due to follow up, threat to validity (selection bias, history - people change exposure over time, instrumentation - tests for cancer change over time, testing - if people aware of outcome hawthorne effect can occur)

Front 17

Non experimental - Retrospective

Back 17

- Strengths: Fewer participants (know outcome), large # of variables
- Weakness : Very diff to find adequate control group, threats to validity

Front 18

Descriptive

Back 18

- Control some threats

Front 19

Other quantitative studies (not diff designs)

Back 19

- Methodological: Develop new tools or test existing ones in new populations/situations
- Meta-analysis: Statistical, pool data from studies of same design
- Secondary data analysis: descriptive, analysis or reanalysis of data for reason other than why it was collected