Clinica urologica, università di Padova Materiali e metodi Giacomo Novara Clinica urologica, università di Padova giacomonovara@gmail.com 1

Materials and methods Material and methods section is the core of each paper It describes how the study was designed, and performed as well as the way the data were analyzed It has to provide all the elements to allow other authors to reproduce the study

Materials and methods It is the easiest part of the manuscript to write Writing this section of the paper in the most complete way before starting the study can help to discover methodological biases in a moment when they are easily fixed!

Materials and methods Period of enrolment/evaluation Type of study (retrospective; prospective; controlled; randomized) Inclusion criteria / patient selection Exclusion criteria / reasons to exclude patients

Materials and methods Details on used materials or technique - report in detail original methods/techniques - cite (and reference) known methods Ethical issue

IRB approval Clinical setting Quality control Inclusion criteria Exclusion criteria Detail on centers involved (added on reviewer’s request)

Description of surgery of the primary tumor and lymph node Description of pathology procedure TNM staging system and grading system Describe in detail what is of central relevance or not standardized or not well known

Materials and methods Description of follow-up protocols Definition of the events (disease recurrence and death of disease)

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www.consort-statement.org

Methods section in RCT – Consolidated Standards of Reporting Trials (CONSORT) statement www.consort-statement.org

What methods section should NOT include Study results (by definition, they go in the “Results” section) Comments on patients characteristics, indications, inclusion and exclusion criteria (they go in the “Discussion” section)

Statistical analysis Should cite the tests which have been used in the different circumstances The choice of the statistic test depends on the nature of the variables categorical variables continuous variables (parametric; non parametric)

Methods section and statistical analysis The continuous variables are not all the same! One of the most common mistakes in the papers submitted to Eur Urol I reviewed in the last years

Follow-up duration (slide from Prof. Studer) 6 4 2 1 15 ≤ 1 year: 18/20 (90%) 14 years median 0.5 year (IQR 0.3-0.75, range 0.25-15) mean 2 years (SD ± 4.5, SEM ± 1)

Statistical analysis Reference only the test which are not well known Report the p value for statistical significance (p<0.05 - probability of a false positive result) Provide an estimation of the study power (beta error – probability of a false negative result) Specify the used software

Methods section and statistical analysis Comparisons of categorical and continuous variables Survival function, univariable and multivariable analyses Detail on an uncommon statistical issue (interaction terms in multivariable models) P values and software

Statistical analysis Very complex statistical tests are seldom useful Whenever used, they should be explained and referenced Fancy statistics are meaningless if not strictly related with the clinical problem What might be hard for an experience reviewer will be impossible to understand for most of the readers

Who should run the statistics? An experienced biostatistician is the best option, whenever available (although he might struggle to focus on the clinical problem) Being urologist, I usually do 99% of my statistics by myself (no risk of misunderstanding the clinical problem, minimal risk of doing wrong things on routinary statistics)

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