manuscript writing and assessment marko turina university of zurich switzerland

MANUSCRIPT WRITING AND ASSESSMENT

Marko TurinaUniversity of Zurich

Switzerland

This is an interactive session; be free to interrupt and ask

questions at any time during the talk!

You want to perform a scientific study.What type of a study is possible for a

CT surgeon?• Experimental (laboratory) study: CT

surgeons are nowadays poorly qualified for such work.

• Retrospective study: becoming less popular, but most advances in CT surgery resulted from such studies.

• Cohort study: scientifically higher rated, but lasts longer, and more difficult to perform.

• Prospective study, if possible randomized. Highest level of scientific evidence, but unattainable for CT most surgeons: very complex and expensive, needs strong financial background

• Meta-analysis: needs a good statistician, but might give interesting results

Study beging

Retrospective study

Retrospective study

• Material about a particular procedure or disease is collected from clinical records.

• Comparison group with same condition, but with different treatment (or none at all) is derived from same period.

• Results are assessed• “Case matching” (age, gender, disease

extension, etc.) is performed.• Drawback: unrecognized bias is possible

Prospective cohort study

Retrospective cohort study

Cohort study

• A group of patients with a particular disease or after a certain procedure are observed over time.

• Can be either prospective or retrospective

• Advantage: avoids randomization, which can be unethical (e.g. withdrawing operation or treatment)

• Disadvantage: due to lack of randomization, observed results can be due to some other factors than those studied.

Copyright ©2010 American Heart Association

Morice, M.-C. et al. Circulation 2010;121:2645-2653

SYNTAX trial schematics

Prospective (randomized) study

• An intervention (surgery) is offered to one group, and alternative procedure to the other.

• Preferably, selection of patients for each group is made by randomization.

• “Double-blinding” is rarely possible in surgery• Results are assessed after a specified period

of time• Drawback: Takes a long time, very expensive,

needs a large number of patients when differences are small.

• Due to difficulties in recruiting, results are often not representative of “real-life” data.

Levels of Evidence

Level A

Level B

Level C

You have collected the data and would like to write a manuscript: how to

proceed?First, analyze your data carefully: the

essence of science is the analysis. Do not simply unload your data into tables and figures, add text and send it somewhere.

“Observations are useless until they have been interpreted. The analysis of experimental data forms a critical stage in every scientific inquiry – a stage which has been responsible for most of the foolishness and fallacies of the past”

E. Bright Wilson, An Introduction to Scientific Research.

Where to send the manuscript?

• Circulation, JACC, NEJM, JAMA have very high impact factor and accept < 8 % of submitted manuscripts: only the very best material qualifies.

• JTCVS, Annals and EJCTS have similar impact factor; their acceptance rate is ~ 25-30 %

• Papers presented at annual meeting of large associations have somewhat better chance of acceptance, because congress material should be published.

• Specialized work (TX, assist devices, cell technology) has better chance in specialised journals: JHLTPL, ASAIO journal, Cell, Nature, etc.

http://www.ctsnet.org/sections/journalsandbooks/writersresource/index.html

EJCTS instructions for manuscript submission

EJCTS instructions for manuscript submission

EJCTS instructions for manuscript submission

A word of caution about the dominance of statistics in today's science (not to be interpreted as speaker’s

backwardness)

Do not be misled by statistical associations: they can be completely erroneous

Courtesy of Pieter Kappetein, EACTS

Beware of multiple subgroup analysis!!

Circulation 1980; 61(3):508-15

Simple rules which researchers should remember when attacking their data with some massive statistical effort.

• Statistical end result (p value, Χ2) shows only the degree of association; it says nothing whatsoever about causal relationship (“Torture the data until they confess….”).

• Beware of “Post hoc, propter hoc” logic: temporal relationship of two variables (one occurring after the other) does not mean that it is a “cause and effect” relation.

• With large hospital or national data banks now required by law in many countries, “data mining” can be very productive, but this is not science: results can be valid only if a previously determined hypothesis is being evaluated.

Nevertheless, the rules about statistician’s participations are

clear in most journals

JTCVS rules

Watch your numbers when writing manuscript!

From a recently submitted manuscript (it was rejected)

Check your English when writing manuscript!What is “idoneous”?

For authors who are not native English speakers, it is a good practice to elicit help from expert translator/assistant. In Latin, “idoneous” means “suitable”

Check your English when writing manuscript!Avoid strange abbreviations!

BLSD stand for “Basic life support defibrillation”, BAVIII in Italian probably for “Bloco atrioventriculare III”

Try to avoid abbreviations: they make your manuscript difficult to read, and are usually

unnecessary”Cardioplegia (C) is a type of ischemia-reperfusion injury (IR),

usually it is connected with hypothermia (H). IR causes myocardial stunning (MS). MS occurring after IR has been extenisively investigated, both the metabolic consequences (MC), the gene programs (GP) activated, the ione shifts (IS) occurring, etc. ”

“The role of MC, GP, and IS in C-induced IR is not fully known, neither are the exact cellular events of MS. HCA is important to protect the heart”

Did Tolstoy use abbreviations in ”War and Peace”?

Did Hemingway use abbreviations in ”The old man and the sea”?

After Jarle Vaage, Prague 2008

Some remarks about p-value

• What is the real difference between p=0.046 and p=0.054?

• There is a major difference between “Significant” and “Clinically relevant”.

• Don’t present your p-values as either p<0.05 or NS (for non-significant): Give exact p-values and let the reader evaluate the importance

• Acceptable: p<0.001 and p>0.2, in between give exact p-values like: p=0.006, p=0.027

After Jarle Vaage, Prague 2008

In statistics, use numbers which were actually measured, not calculation-derived artifacts. This

error is surprisingly common in many submissions.

Do not write:• Cardiac output was 5.389 ± 0.439 L/min• Blood pressure increased from 138.916 ± 31.937 …• Positive effect was observed in 55.6 % of patients …• Avoid percentages in small numbers (< 30)

Instead, use:• Cardiac output was 5.4 ± 0.4 L/min• Blood pressure increased from 139 ± 32 …..• Positive effect was observed in 5/9 patients.

After Jarle Vaage, Prague 2008

Honest use of error bars• Using SEM is a cheap trick, because it depends

on the number of observations, and does not give proper information on variability.

• SEM = SD divided with the square root of the number of observations, for instance: N=49, SD=14, then SEM = 14:7 = 2

• SEM may sometimes be used in figures with longitudinal data and several groups to avoid too much overlap.

After Jarle Vaage, Prague 2008

Refrain from statistical tricks: same data with SEM on the left, with 95 % confidence

limits on the right.

mean ± SEM mean ± 95% confidence intervals

After Jarle Vaage, Prague 2008

When dealing with small numer of observations, use scatter plots and

median values

After Jarle Vaage, Prague 2008

Be painstakingly honest in your data collection and

analysis!

A BETTER-KNOWN EXAMPLE OF SCIENTIFIC FRAUD

Bezwoda’s report to ASCO, analysed in Lancet 2000;355:9208

Beware of two deadly sins in scientific publishing:

Plagiarism

Redundant (duplicate) publication

Plagiarism can mean the end of an career, and it is easy to detect!

By all means, avoid plagiarism: reviewers are experts, and there are electronic means of detecting duplicate submissions or “borrowed” material. Avoid “Copy and Paste” technique, even from your own material: use of this technique can easily result in a duplicate publication!

Simple plagiarism check with Google Scholar from a recent publication

Simple plagiarism check with Google Scholar: Quick results

In US, plagiarism is a punishable offense, with a governmental agency supervising research, and taking

administrative actions.

Beware of two deadly sins in scientific publishing:

Plagiarism

Redundant (duplicate) publication

EJCTS instructions for manuscript submission

All 6 conditions must be met to declare a publication as a duplicate one.

Definition of duplicate publication is well known, so avoid it!

The publication will be considered as duplicate, or redundant, when:

• Hypothesis is the same or similar.• Methods are identical.• Case material is similar, or somewhat

larger.• Results are identical, or nearly so.• Several authors are common to both

publications.

Similar bad practice is “Salami publishing” or “Parma manuscripts”

(thinly sliced material)

Your data should be submitted fully; do not try to send a part of it to one journal and the other part to another one. Editors and reviewers consult each other, and they meet often; so this action will be detected, and will give you bad reputation. This particular practice is often used to inflate author’s publication list; but it is detested and fought by editors, because it burdens journals and readers with similar material.

Rules for manuscript submission in EJCTS

Rules for manuscript submission in Annals of Thoracic Surgery

Rules for Annals of Thoracic Surgery: editors want originality!

Authorship rules are nowadays very strict:

no more honorary authorships!

Manuscript’s authorship: some advices

• Settle all authorship problems before beginning to write the manuscript: you will save yourself a lot of trouble later.

• First author is the researcher who performed most of the work, and/or wrote most of the manuscript.

• Senior author is acknowledged to be the originator of the idea/hypothesis, or in charge of the group submitting the manuscript.

• Having performed some or even a large part of surgeries described in the manuscript does not necessarily qualify for authorship, unless other criteria are met.

What not to do when submitting a manuscript

• Start discussion with the editor to be exempted from the journal’s rules (number of authors, or literature citations, or word count - because you are obviously so important). You will quickly find yourself in the possession of your returned manuscript.

• Explain that a similar version has been presented elsewhere, or has already been published, but you added some patients/experiments/numbers. Editors want originality for their journals.

• Try to disguise previous rejection of the same material (e.g. send “Ultra Mini-Abstract” to EJCTS – where it is needed only in JTCVS, and was obviously rejected there).

A good manuscript concentrates on essentials,

and avoids long-winded explanations.

The best way to be boring is to leave nothing out.

Voltaire (1694 -1778)

This is an example of a good “Introduction” section

Medawar’s Nature article about immunotolerance

What is the lesson here? You can win Nobel prize for medicine with a 3 ½ pages article, with 15

references.So, make your manuscripts short, containing only essential details,

and avoid verbiage! “Brevity is the soul of wit”.

How to shorten the manuscript?

• Standard methods (e.g. cannulation, cardioplegia, statistics, etc.) can be referenced (as previously described in # …, or according to Guidelines in # …).

• In discussion, mention only the most relevant, recent papers. Do not start with 200 BC, etc.

• Larger amount of numerical data belongs to tables and figures; in text you only comment upon the data, you should not repeat them.

• Avoid duplication: either text, or figures and tables; not both.

Highest chance of successful submission

• Properly designed prospective randomized study • In non-randomized trials, apply proper statistical

methods (e.g. propensity score, matching pairs). Statistician must be consulted, and he is one of the authors!

• Meta-analysis is assuming increasing importance, but it is difficult to perform properly (selection of papers to be analyzed, double counting material!).

• Innovative work has a high chance of acceptance: new techniques, ideas, experimental observations.

• Attractive are also manuscripts which question an established belief or a widely presumed “fact”.

• Novel classification or guidelines: this guarantees highest number of citations in a short time.