Research methods and study design

Meet the classic series

In 2002, Grimes and Schulz published a four-paper series in The Lancet — "the lay of the land," cohorts, case-control ("research in reverse"), and bias — that is still the cleanest map of study design any registrar will read.^[1]

Their core teaching is one sentence: design is destiny. The structure of a study decides what claim it can defend. A cohort marches forward to outcomes; a case-control works backward from the outcome to exposure; a cross-sectional snapshot cannot establish temporality. Pick the wrong design and no amount of clever statistics rescues the claim.^[2][3][4]

This topic is that map, applied to psychiatry. The arithmetic of finished papers — NNT, forest plots, I-squared, GRADE certainty — lives in the critical-appraisal and biostatistics topics. Here we own the blueprint, not the audit.^[1][17]

References20ShowHide

1. [1]Grimes DA, Schulz KF An overview of clinical research: the lay of the land Lancet, 2002.PMID 11809203
2. [2]Grimes DA, Schulz KF Cohort studies: marching towards outcomes Lancet, 2002.PMID 11830217
3. [3]Grimes DA, Schulz KF Case-control studies: research in reverse Lancet, 2002.PMID 11844534
4. [4]Grimes DA, Schulz KF Bias and causal associations in observational research Lancet, 2002.PMID 11812579
5. [5]Schulz KF, Altman DG, Moher D; CONSORT Group CONSORT 2010 statement: updated guidelines for reporting parallel group randomised trials BMJ, 2010.PMID 20332509
6. [6]von Elm E, Altman DG, Egger M, Pocock SJ, Gøtzsche PC, Vandenbroucke JP; STROBE Initiative The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement: guidelines for reporting observational studies Lancet, 2007.PMID 18064739
7. [7]Page MJ, McKenzie JE, Bossuyt PM, et al. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews BMJ, 2021.PMID 33782057
8. [8]Moher D, Liberati A, Tetzlaff J, Altman DG; PRISMA Group Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement BMJ, 2009.PMID 19622551
9. [9]Schulz KF, Chalmers I, Hayes RJ, Altman DG Empirical evidence of bias. Dimensions of methodological quality associated with estimates of treatment effects in controlled trials JAMA, 1995.PMID 7823387
10. [10]Hollis S, Campbell F What is meant by intention to treat analysis? Survey of published randomised controlled trials BMJ, 1999.PMID 10480822
11. [11]Sterne JAC, Savović J, Page MJ, et al. RoB 2: a revised tool for assessing risk of bias in randomised trials BMJ, 2019.PMID 31462531
12. [12]Sterne JA, Hernán MA, Reeves BC, et al. ROBINS-I: a tool for assessing risk of bias in non-randomised studies of interventions BMJ, 2016.PMID 27733354
13. [13]Guyatt GH, Oxman AD, Vist GE, et al. GRADE: an emerging consensus on rating quality of evidence and strength of recommendations BMJ, 2008.PMID 18436948
14. [14]Hill AB The environment and disease: association or causation? Proc R Soc Med, 1965.PMID 14283879
15. [15]Tong A, Sainsbury P, Craig J Consolidated criteria for reporting qualitative research (COREQ): a 32-item checklist for interviews and focus groups Int J Qual Health Care, 2007.PMID 17872937
16. [16]Richardson WS, Wilson MC, Nishikawa J, Hayward RS The well-built clinical question: a key to evidence-based decisions ACP J Club, 1995.PMID 7582737
17. [17]Sackett DL, Rosenberg WM, Gray JA, Haynes RB, Richardson WS Evidence based medicine: what it is and what it isn't BMJ, 1996.PMID 8555924
18. [18]Altman DG, Bland JM Absence of evidence is not evidence of absence BMJ, 1995.PMID 7647644
19. [19]Ioannidis JPA Why most published research findings are false PLoS Med, 2005.PMID 16060722
20. [20]Higgins JP, Thompson SG, Deeks JJ, Altman DG Measuring inconsistency in meta-analyses BMJ, 2003.PMID 12958120