SPH1904 Midterms Flashcards
Rank the following on the evidence pyramid :
- randomised controlled trials (RCTs)
- critically-appraised individual articles (article synopses)
- cohort studies
- case-controlled studies (case series/reports)
- background information/expert opinion
- systematic review
- critically-appraised topics (evidence syntheses)
From strongest to weakest evidence :
- systematic review
- critically-appraised topics (evidence syntheses)
- critically-appraised individual articles (article synopses)
- randomised controlled trials (RCTs)
- cohort studies
- case-controlled studies case series/reports
- background information/expert opinion
What does the PICO framework stand for?
P - Patient
I - Intervention
C - Comparison
O - Outcome
Rank the study designs for a Therapy/Prevention Question
RCT > Cohort > Case-control > Case series
Rank the study designs for a Etiology/Harm Question
RCT (rarely) > Cohort > Case-control > Cross-sectional
Rank the study designs for a Prognosis Question
Cohort > Case-control > Case series
Rank the study designs for a Diagnosis Question
Prospective, blind comparison to a gold standard
List the Boolean operators and how to perform a search
- – Include all forms of the same word
AND – Include words of different topics/concepts
OR – Include words of similar topics/concepts
What does the CRAAP tool stand for?
C : Currency – timeliness of information
R : Relevance – importance of information for your needs
A : Authority – source of information
A : Accuracy – reliability, truthfulness and correctness of the content
P : Purpose – the reason the information exists
For each of the following study designs [Cross-sectional study, Case-control study, Cohort-study, RCT] , answer the following questions :
1. When are the exposure and outcome measured?
2. Are participants matched on the outcome?
3. Are participants randomised to the exposure?
Case-control : Outcome measured after the exposure ; Participants matched on the outcome ; Participants not randomised to the exposure
———-
Cohort study : Outcome measured after the exposure ; Participants are not matched on outcome ; Participants are not randomised to the exposure
———
RCT : Outcome measured after the exposure ; Participants are not matched on outcome ; Participants are randomised to the exposure
List the Bradford-Hill criteria.
TSBDECCSA
1. Strength: A larger effect size makes it more likely that the association is causal.
2. Temporality: Cause must precede effect
3. Consistency: Multiple studies showing the same findings increase the credibility
4. Biological Plausibility: A rationale or theoretical basis for the finding
5. Dose response relationship: Greater the amount of exposure, the greater amount of harm
6. Experimental Evidence: Experiments make a causal association more plausible
7. Coherence: Cause-effect relationship doesn’t conflict with what is known or has other competing hypotheses
8. Specificity: Effect has only one cause
9. Analogy: A commonly accepted phenomenon in one area can be applied to another area
Define prevalence.
The frequency/number of cases in a specific population who have a specific condition during a specified time region (e.g. all current cases within a specific time frame)
Define incidence.
Incidence is the frequency/occurrence of a new outcome of interest during the specified time period being examined.
Explain the characteristics, benefits and limitations of each of the following sampling methods (Non-probability sampling, Simple Random Sampling, Stratified Sampling, Cluster Sampling, Systematic Sampling)
Non-Probability Sampling :
- Characteristics – Selects samples based on non-random criteria like convenience or judgement
- Benefits – Easy, Quick and Cost-effective
- Limitations – Biased, not representative, findings cannot be generalised
Simple Random Sampling :
- Characteristics – Every member of the population has an equal chance of being selected
- Benefits – Unbiased, easy to understand, generalisable results
- Limitations - Challenging for large populations, potential to miss segments
Stratified Sampling :
- Characteristics – Divides population into subgroups ; samples from each subgroup
- Benefits – Represents all segments, more accurate, reduces sampling error
- Limitations – Requires population knowledge, complex, higher costs
Cluster sampling :
- Characteristics – Divides populations into clusters ; selects entire clusters randomly
- Benefits – Economical for large areas, reduces costs and logistical issues
- Limitations – Higher sampling error, less precision, clusters may vary internally
Systematic Sampling :
- Characteristics – Selects members at a fixed interval from a randomly chosen starting point
- Benefits – Simple, suitable for large populations
- Limitations – Risk of periodicity bias, not truly random, ordered list required
List the data type, numerical summary, graphical display (1 variable) and graphical display (2 variables) for categorical and numerical data respectively.
Categorical data :
[Data type] Nominal : Response categories with no order and Ordinal : Response categories with order
[Numerical summary] Frequency, n ; Percentage, %
[Graphical display (1 variable)] : Bar chart
[Graphical display (2 variables)] : Grouped Bar charts, Multiple boxplots (mixed data)
Numerical data :
[Data type] Continuous / Discrete
[Numerical summary] Normally distributed, Skewed division, Mean, Standard deviation, Median, Range median, IQR
[Graphical display (1 variable)] : Histogram/Boxplot ; Mean, Mode, Median
[Graphical display (2 variable)] :
Scatter plots, Pearson/Spearman Correlation Coefficient, Multiple boxplots (mixed data)
Define sensitivity.
Probability of correcting identifying persons with the disease.
