1. Materials & Methods what to include and where
Anthony M. Vintzileos, MD

2. Materials & Methods (clarity) Results (transparency)
One of the Most Important Criteria for Accepting Manuscripts for Publication
Is Report likely to be true or correct?
Materials & Methods (clarity)
Results (transparency)

3. Materials & Methods Reporting guidelines (depend on study design)
CONSORT
PRISMA
MOOSE
STARD
STROBE

4. Vintzileos and Ananth AJOG 2010;202:344.e1-6
Materials & Methods
Clarity is essential
Define clearly the type of study (prospective, retrospective, case-control etc)
Sample size estimation (based on primary outcome)
Definition (demographics) of study and control groups (or comparison groups)
Clear definitions of exposures, primary and secondary outcomes
Inclusion and exclusion criteria
Types of measurements used for primary and secondary outcomes
Data extraction methodology
Clear description of methods, procedures or tests
Brief description of methods or procedure (if previously published)
IRB approval and type of consent, if applicable
Use of Tables or Figures may or may not be necessary
Methods of statistical analysis and levels of significance
Is there enough detail for the study to be reproduced?
Vintzileos and Ananth AJOG 2010;202:344.e1-6

5. Accuracy of Diagnostic Tests:
TIPS
Accuracy of Diagnostic Tests:
Sensitivity*
Specificity*
Positive predictive value
Negative predictive value
* Not influenced by the prevalence of the disease
(not always true)

6. TIPS Sensitivity Specificity Positive predictive value
Accuracy of Diagnostic Tests:
Sensitivity
Specificity
Positive predictive value
Negative predictive value
The main question:
Was there any intervention based
on abnormal test results which
may have altered the outcome of interest?

7. “Biostatisticians’ Conspiracy”
TIPS
What Cutoff of a Continuous Variable (Predictor) Should We Use for Prediction?
“Biostatisticians’ Conspiracy”
10%?
5%?
1%?

8. The “Anathema” of Arbitrary Categorization of Continuous Predictors
Pitfalls in obstetric practice (aneuploidy screening, maternal age, BMI, CL)
Pitfalls in research (loss of statistical power)
Vintzileos et al Am J Obstet Gynecol 2014;210:200-3

9. Consider Using Receiver Operating Characteristic Curve (ROC curve) to Determine Optimal Cutoff
The AUC is the measure of accuracy (ideal for comparing diagnostic accuracies of continuous variables)
First, determine the outcome of interest
Sensitivity (true positive rate) vs. FPR (1-specificity) of various cutoffs
Ideal for establishing (before interventional trials) the most optimal cutoff
The most optimal cutoff may vary according to the outcome of interest and clinical circumstances
AUC
AUCs
EXAMPLE
CL cutoff for preterm labor < 25 mm
CL cutoff for labor at term < 15 mm

10. Materials & Methods
Be prepared to give results for all outcome measures described under “Materials & Methods”