Emiliano Chisci. Chirurgia Vascolare USL Toscana Centro San Giovanni di Dio - Firenze

Transcription

1 Emiliano Chisci Chirurgia Vascolare USL Toscana Centro San Giovanni di Dio - Firenze

2 The components of a scientific article: IMRAD (1979) Based on principles derived from the content and sequence of the critical argument Consists of Introduction: why did you do the study? Materials and methods: what did you do? Results: what did you find? (AND) Discussion: what does it mean? There isn t much room for creativity, but at the same time, it simplifies the writing process

3 Risultati Cosa abbiamo trovato? I dati andrebbero presentati in forma chiara, concisa, ponendo l accento su cosa è rilevante I risultati andrebbero presentati tutti (incluso quelli negativi o non significativi )

4 Risultati Il testo dovrebbe descrivere la ricerca Le tabelle dovrebbero far risaltare le evidenze Le figure/grafici dovrebbero illustrare i punti salienti

5 Come si presentano Testo: racconta la storia Tabelle: riassumono i risultati Figure: evidenziano trend, distribuzioni etc Analisi statistica: supporta i risultati riportati

6 Risultati Rispondere alle domande poste nell introduzione 3 modi di presentare : 1) Dal più semplice al più sofisticato (es. univariata, bivariata, multivariata) 2) Dalla più importante alla meno importante 3) In sequenza temporale come quella dello studio Huth, EJ. Writing and publishing in medicine. Third edition. Baltimore: Williams and Wilkins, 1999

7 Differenza tra dati e risultati Dati Fatti, Numeri,Tassi Medie,Rischi,Probabilità Limiti di confidenza Risultati Ci dicono che significano I dati Sono presentati nel testo Tabelle e grafici Non ripetono I dati già presentati in tabelle e grafici

8 Results The Beginning The heart of your paper Write after figures and tables are constructed Consider your data critically Construct tables, figures and include them in outline Write the results Use subheadings

9 Results The Beginning State ALL the findings Whether significant or not Without bias or interpretation Do not include weaknesses, strengths of study, ie don t discuss results List experiments in order listed in methods Use logical headers and group your findings Characteristics of study subjects Findings in order listed in methods General to specific Use past tense Results confirm or reject your hypothesis: they do not prove anything.

10 Results Short and to the point Main or most important findings first Present only data directly relevant to the study focus Don t repeat methods but you may remind the reader briefly how you measured something. Allow the data to speak for itself use tables/figures construct them first and use as a basis for writing In Tables and Figures, be descriptive, specific. Do not repeat the obvious: NO: Results of the kidney lead analysis are shown in Table 1. YES: Kidney lead concentrations increased in group 1 over the first 10 study weeks (Table 1). Present absolute numbers and percentages so reviewers can judge the significance of the findings. Statistical significance clinical significance

11 Results Results should be followed by statistical test method and P value where appropriate. For example: Group A is significantly taller than group B (t = 2.171, d.f. = 29, P < 0.05).

12 Results or Data? Results Mean translational movements in the X (left to right), Y (back to front) and Z (bottom to top) head directions were 0.10 ± 0.11 mm, 0.16 ± 0.03 mm, and 0.65 ± 0.58 mm, respectively. Mean rotational movements about the three axes were 0.44 ± 0.42 degrees, 0.24 ± 0.26 degrees, and 0.18 ± 0.17 degrees, respectively. Movement was not significantly correlated with age for translation in the X (r = -0.09; p = 0.69), Y (r = 0.21; p = 0.35) or Z (r = -1.02; p = 0.64) directions. Movement was not significantly correlated with age for rotation in the X (r = 0.15; p = 0.51), Y (r = -0.20; p = 0.35) or Z (r = 0.02; p = 0.94) directions.

13 Results!

14 Results Don t Regurgitate Data As shown in Table 1, the mean age of participants was 20.4 ± 2 years, and 80% of patients were Caucasian. Treatment group contained 40 patients, whereas control group contained 45 patients. Table 2 shows the demographics of women in these groups. There were 24 women in the control group, and 33 women in the treatment group... There were no significant differences in treatment and control patient intake demographics (Table 1), although a significantly greater number of patients in the treatment group dropped from the study for a variety of reasons, mostly relating to adverse reactions. However, analysis of patients in this group later revealed that those dropped patients had significant disease at intake (Table 2). In comparing the two treatment groups (Figure 1), we found that...

15 Don t State the Obvious Figure 1 is a graph illustrating the plasma zinc levels (µmol/l) over the 37 weeks versus gestational age in both the zinc supplement group and placebo group. The placebo and the zinc group both decreased over the 37 weeks of the study, but the differences were significant for the zinc group.

16 State What s Important We measured mothers plasma zinc levels before randomization (week 19) and at 26, 32, and 37 weeks gestational age (Fig 1). Beginning as early as 26 weeks and at each timepoint, differences in plasma zinc levels between placebo and zinc supplement groups were statistically significant (P 0.05) after randomization.

17 Results Major Mistakes Failure to provide all the data critical to answering the research question Interpreting or commenting on results Six of the 20 patients required intubation, illustrating the seriousness of this problem (belongs in Discussion) Over 40% of treated rats exhibited a decreased inflammatory response, an unexpected finding (belongs in Discussion) Failure to adequately address statistical methods Tables and figures inappropriate, unbalanced Tables and figures poorly constructed

18 Tables and Figures Critical to a paper Editors and readers look at these before reading the paper! Editors judge your paper on how well these are constructed Stand alone and tell a complete story Unambiguous immediately clear Eliminate numerical data and long explanations in text Figures display important trends, procedures, simplify detailed data, and show basic methodologies.

19 Tables This requires a table!

20 Tables This result does NOT require a table! Growth medium aeration was essential for the growth of S. coelicolor. At room temperature (24 C), no growth was measurable in stationary cultures, whereas in aerated cultures, we measured substantial growth (78 Klett units).

21 Tables & Result In women with BMI <26 kg/m 2, zinc supplementation was associated with a significant increase in birth weight of 248 g (P=0.005), an increase in head circumference of 0.7 cm (P=0.005), and increase in arm length of 0.3 cm (P=0.03). The other outcome measures all favored the zinc supplement group but the differences were not statistically significant (Table 2).

22 Table & Result Table 3 shows the mean birth weight by the BMI categories recommended by the NIH Institute of Medicine. The lower the BMI, the greater the effect of zinc supplementation on birth weight.

23 Patient Disposition (Results) Complex Study Design Simplified

24 Bar or Line Graphs-Colors? This graph will appear in the journal like this: Journals DO NOT allow color graphs unless they are necessary for understanding the graph

25 Simple Graph Use graphing software in word/powerpoint to create: KISS No more than 3-4 groups Keep all lines solid, few symbols Put in SD and P values if relevant

26 Discussione Dopo l abstract e l introduzione è la parte più letta Focalizzati su cosa significano i risultati e quale contributo danno al settore E la parte più difficile da scrivere Annesley TM. Clinical Chemistry Guide to Scientific Writing 2010

27 Discussione In ordine: Che cosa dimostra il tuo studio in relazione all iniziale ipotesi (1 paragrafo) In che modo il tuo studio sostiene o critica l attuale conoscenza? (comparazione +/-, più paragrafi) Non esagerare con references Quali i limiti dello studio (1 paragrafo) Annesley TM. Clinical Chemistry Guide to Scientific Writing 2010

28 Discussione E ALLORA?? -Quali le conseguenze del tuo studio? -Che direzione deve prendere il lavoro in questo campo? ( paragrafo finale ) In sintesi: dallo specifico al più generale Annesley TM. Clinical Chemistry Guide to Scientific Writing 2010

29 Discussion Construction Summarize major findings 1st paragraph Explain how your findings relate to those of others what do they mean? Clinical relevance of the findings? Limitations and how this influenced your study? How will you overcome these in the next studies? Explain the implications of findings What future direction(s) will you take?

30 Discussion: Getting Carried Away Few studies make discoveries changing the course of scientific direction, and so authors: Attempt to overly state or the importance of their findings Come to erroneous or unsupported conclusions Uncritically accept statistical results This all distracts from work s importance and signals to the reviewer problems with the research Also results in excessive length, a common problem Authors should let the data speak for themselves

31 Discussion Common Mistakes 1. Unwarranted speculations 2. Injecting tangential issues 3. Conclusions not supported by the data 4. Not suggesting future directions for research hypothesis Ô study Ô data/results Ô conclusions TIGHT PACKAGE

32 Day and Gastel