Scientific Critical Thinking
Systematic evaluation of research rigor through methodology assessment, bias detection, and evidence quality frameworks.
Triggers
- User asks to evaluate a study's quality
- User needs to assess evidence strength
- User is reviewing trial methodology
- User wants to identify limitations or biases
- User is critiquing research for an editorial
Core Capabilities
1. Methodology Critique
Validity Assessment: | Type | Question | Red Flags | |------|----------|-----------| | Internal | Did the study measure what it intended? | Confounders, selection bias | | External | Can results generalize? | Narrow population, artificial setting | | Construct | Do measures capture the concept? | Surrogate endpoints, proxy measures | | Statistical | Are conclusions supported by data? | Underpowered, multiple testing |
Study Design Hierarchy:
- Systematic reviews/meta-analyses of RCTs
- Individual RCTs
- Cohort studies
- Case-control studies
- Cross-sectional studies
- Case series/reports
- Expert opinion
2. Bias Detection
Cognitive Biases in Research:
- Confirmation bias: Interpreting data to support hypothesis
- HARKing: Hypothesizing after results known
- Publication bias: Positive results published more
- Spin: Overstating or misrepresenting findings
Selection Biases:
- Sampling bias (non-representative)
- Volunteer bias (healthier participants)
- Attrition bias (differential dropout)
- Survivorship bias (only studying survivors)
Measurement Biases:
- Observer/detection bias
- Recall bias
- Social desirability bias
- Hawthorne effect
Analysis Biases:
- P-hacking (multiple testing)
- Outcome switching
- Selective reporting
- Data dredging
3. Statistical Evaluation Checklist
- [ ] Sample size adequate? (power analysis done?)
- [ ] Statistical test appropriate for data type?
- [ ] Multiple comparison correction applied?
- [ ] Effect sizes reported (not just p-values)?
- [ ] Confidence intervals provided?
- [ ] Missing data handled appropriately?
- [ ] Assumptions of tests verified?
4. Evidence Quality Assessment (GRADE)
Quality Levels: | Level | Meaning | Implications | |-------|---------|--------------| | High | Very confident in estimate | Strong recommendation | | Moderate | Moderately confident | Conditional recommendation | | Low | Limited confidence | Further research likely | | Very Low | Little confidence | Estimate highly uncertain |
Downgrade Factors:
- Risk of bias
- Inconsistency across studies
- Indirectness (surrogate outcomes)
- Imprecision (wide CIs)
- Publication bias
Upgrade Factors:
- Large effect size
- Dose-response relationship
- Residual confounding would reduce effect
5. Logical Fallacy Detection
Causation Fallacies:
- Post hoc ergo propter hoc (after = because of)
- Correlation ≠ causation
- Reverse causation
- Confounding as causation
Generalization Errors:
- Hasty generalization (small sample)
- Ecological fallacy (group to individual)
- Exception fallacy (individual to group)
Statistical Fallacies:
- Texas sharpshooter (finding patterns in noise)
- Base rate neglect
- Regression to mean confusion
- Multiple endpoints fishing
6. Research Design Questions
When evaluating a study, ask:
- Question: Is the research question clear and answerable?
- Design: Is the study design appropriate for the question?
- Population: Is the sample representative of target population?
- Intervention: Was the intervention clearly defined and consistent?
- Comparison: Was the control group appropriate?
- Outcome: Were outcomes clinically meaningful and measured reliably?
- Follow-up: Was follow-up long enough and complete enough?
- Analysis: Was the analysis appropriate and pre-specified?
7. Claim Evaluation Framework
For any scientific claim:
- Identify the assertion - What exactly is being claimed?
- Evaluate supporting evidence - What studies support it?
- Check logical connection - Does evidence actually support claim?
- Assess proportionality - Is strength of claim proportional to evidence?
- Detect overgeneralization - Are limits of findings respected?
- Flag red flags - Conflicts of interest, spin, p-hacking?
Application to Cardiology Content
Evaluating Trial Results
- Check randomization and blinding adequacy
- Assess primary endpoint clinical relevance
- Evaluate intention-to-treat vs per-protocol
- Look for protocol changes mid-trial
- Examine subgroup analyses critically
- Consider funding source influence
For Editorials/Newsletters
- Acknowledge study limitations explicitly
- Don't overstate findings
- Note where evidence is weak
- Distinguish association from causation
- Highlight what questions remain
Critique Output Format
When critiquing research:
- Summary: Brief overview of what study did
- Strengths: What was done well
- Critical concerns: Major methodological issues
- Important limitations: Secondary concerns
- Minor issues: Small points for completeness
- Overall assessment: Balanced conclusion on reliability