6. Biostatistics Notes

“Improving the Research Methodology and Biostatistics in Health Research”

Dates of Project Initiation and Completion: [January 2015] – [Ongoing]

Resulting Publications

(1) Alireza Baratloo, Mostafa Hosseini, Ahmed Negida, Gehad El Ashal: Evidence-Based Emergency Medicine; Part 1: Simple Definition and Calculation of Accuracy, Sensitivity, and Specificity. Emergency (Tehran, Iran) 05/2015; 3(2):48-49.

(2) Saeed Safari, Alireza Baratloo, Mohamed Elfil, Ahmed Said Negida: Evidence-Based Emergency Medicine; Part 2: Positive and negative predictive values of diagnostic tests. Emergency (Tehran, Iran); 06/2015; 3:87-88.

(3) Alireza Baratloo, Saeed Safari, Mohamed Elfil, Ahmed Negida: Evidence-Based Emergency Medicine Part 3: Positive and Negative Likelihood Ratios of Diagnostic Tests. Emergency (Tehran, Iran); 11/2015; 3(4):170-171.

(4) Saeed Safari, Alireza Baratloo, Mohamed Elfil, Ahmed Negida: Evidence-Based Emergency Medicine; Part 4: Pre-test and Post-test Probabilities and Fagan’s nomogram. Emergency (Tehran, Iran); 02/2016; 4(1):48-51.

(5) Saeed Safari, Alireza Baratloo, Mohamed Elfil, Ahmed Negida: Evidence-Based Emergency Medicine; Part 5: Receiver Operating Curve and Area under the Curve. Emergency (Tehran, Iran); 04/2016; 4(2).

(6) Mohamed Elfil, Ahmed Negida: Sampling Methods in Clinical Research; an Educational Review. 12/2016; 4(1)., DOI: 10.22037/emergency. v5i1.15215

(7) Fahim N, Negida A. Sample Size Calculation Guide – Part 1: How to Calculate the Sample Size Based on the Prevalence Rate. Advanced Journal of Emergency Medicine [Internet]. 31Jul.2018 [cited 6Mar.2019];2(4):e50. Available from: http://ajem.tums.ac.ir/index.php/ajem/article/view/101

(8) Fahim NK, Negida A. Sample Size Calculation Guide-Part 2: How to Calculate the Sample Size for an Independent Cohort Study. Advanced Journal of Emergency Medicine. 2019;3(1):e12-.

(9) Fahim, Nadien Khaled, Ahmed Negida, and Ahmed Khaled Fahim. “Sample Size Calculation Guide-Part 3: How to Calculate the Sample Size for an Independent Case-control Study.” Advanced Journal of Emergency Medicine 3, no. 2 (2019): e20-e20.

(10) Negida, Ahmed, Nadien Khaled Fahim, and Yasmin Negida. “Sample Size Calculation Guide-Part 4: How to Calculate the Sample Size for a Diagnostic Test Accuracy Study based on Sensitivity, Specificity, and the Area Under the ROC Curve.” Advanced Journal of Emergency Medicine (2019).

(11) Negida, Ahmed, Nadien Fahim, Yasmin Negida, and Hussien Ahmed. 2019. “Sample Size Calculation Guide – Part 5: How to Calculate the Sample Size for a Superiority Clinical Trial”. Advanced Journal of Emergency Medicine 3 (4), e49. https://doi.org/10.22114/ajem.v0i0.255.

(12) Negida, Ahmed. “Sample Size Calculation Guide-Part 6: How to calculate the sample size for a non-inferiority or an equivalence clinical trial.” Advanced Journal of Emergency Medicine 4, no. 1 (2020): e15-e15.

(13) Negida, Ahmed. “Sample Size Calculation Guide-Part 7: How to Calculate the Sample Size Based on a Correlation.” Advanced Journal of Emergency Medicine 4, no. 2 (2020): e34-e34.

Technical Summary of Work

Understanding research methodology and biostatistics are important skills for physicians to conduct clinical research. Medical education around the world suffers from the lack of proper clinical research training. Therefore, physicians and healthcare workers are responsible to fill this gap by themselves though external training and educational resources. Our work in this field several educational articles published in two PubMed-indexed journals about the diagnostic statistics, sampling, and how to calculate the sample size in clinical research. The aim of these articles is to define, explain, and simplify concepts with clear simplified examples to guide researchers and physicians.

In the first series, we discussed the definitions and calculations of sensitivity, specificity, positive predictive value, negative predictive values, positive likelihood ratio, negative likelihood ratio, pretest and post-test probabilities, receiver operator characteristics curve, area under the ROC curve, Fagan’s nomogram, and sampling methods in clinical research.

In the second series, we discussed the definitions and calculation of the sample size for a single proportion (for a cross-sectional study or survey), for a cohort study, for a case-control study, for a diagnostic test accuracy study, for a correlation study, for a superiority clinical trial, and for a non-inferiority and equivalence trials. These calculations were provided with practical guide to the steps of making the calculation on the statistical analysis software and supported with clear examples.

Summary of the Significance of the Work

This project is important to my field because

Understanding research methodology and biostatistics is important for researchers and physicians in ALL MEDICAL FIELDS. Misuse of statistics and research methodology leads to poorly designed research which wastes the resources and mislead the community. Our educational effort in this field act as guide for physicians and researchers to understand the basic concepts in a simplified way with clear examples so that they can apply correctly in their own research.