Pharmacoepidemiology is at a crossroads. With the increasing availability of large healthcare datasets, transparent research practices are essential for maintaining trust and ensuring scientific validity. In this article, we explore how a proposed transparency statement1 could advance openness and reproducibility in pharmacoepidemiology research.
Transparency in pharmacoepidemiology
The journey towards improved health outcomes begins with transparent and reproducible research. Without clear documentation of study designs, analytical decisions and data sources, reproducing findings – and accurately interpreting them – becomes difficult. Transparency initiatives, including the implementation of open science principles, address these challenges and allow researchers, reviewers, funders and decision-makers to evaluate the validity of the research evidence.
Efforts to improve transparency have gained momentum across research disciplines in recent years. Preregistration of trial protocols, sharing of code and materials, and adherence to reporting guidelines have been adopted by stakeholders across the research lifecycle to make research more accountable, trustworthy and reproducible. In pharmacoepidemiology and outcomes research – where findings have a direct impact on clinical guidelines, regulatory decisions and public health – transparency is a necessity, not an academic ideal. However, open science practices have yet to become a cultural norm for pharmacoepidemiology and outcomes researchers.
An explicit transparency statement
Funders and institutions have not incentivized pharmacoepidemiology researchers to implement open science principles in the conduct and reporting of their studies. For those intrinsically motivated, efforts to declare transparency have been disjointed due to a lack of clear reporting guidance.
To encourage the systematic uptake of open science principles, we propose a structured statement1 that allows investigators to showcase the steps they have taken to enhance transparency and reproducibility in their work.
Building on the Transparency and Openness Promotion Guidelines, the proposed statement offers a detailed, standardized declaration of transparency across five domains, including protocol, preregistration, data, code and reporting checklists (Figure 1). Open Science Badges are integrated as visual indicators of achievement.
Figure 1. Domains of the pharmacoepidemiology transparency statement
![Protocol: The protocol was developed using a structured template. The initial protocol and amendments are available at [provide link].
Preregistration: This study protocol was preregistered prior to conducting analyses at [provide link].
Data: The data are available by [provide contact information and steps to acquire a data use agreement AND/OR a link to synthetic data AND/OR information on how to access data in a protected-access repository].
Code: The code for creating the analytical dataset from the secure data warehouse and code for generating the tables, figures and analysis results for this study is available at [provide link].
Reporting checklists: The manuscript is aligned with guidance from the reporting checklist [name]. The checklist is provided in the appendix.](https://www.openpharma.blog/wp-content/uploads/2025/05/Figure-1-1024x302.png)
Recognizing the barriers faced by pharmacoepidemiology and outcomes researchers, including data use agreements and patient privacy protections, the transparency statement provides a practical mechanism to disclose which aspects of a study are available, where they are available, and what (if any) restrictions to access apply. It also clarifies legal and ethical constraints on data sharing, guiding independent researchers on how to negotiate data use agreements with the data holders.
Take an article presenting the results of a population-based cohort study that assessed the risk of acute and post-acute adverse events after SARS-CoV-2 infection in children and adolescents and evaluated the effectiveness of the BNT162b2 mRNA vaccine among adolescents.2 Using the proposed statement domains above, the transparency statement for this article could have appeared as shown in Figure 2.
Figure 2. An example transparency statement developed using the proposed structure
Additional imagery from Kildegaard H et al. Risk of adverse events after covid-19 in Danish children and adolescents
and effectiveness of BNT162b2 in adolescents: cohort study. BMJ 2022;377:e068898. http://dx.doi.org/10.1136/ bmj-2021-068898. This work is licensed under a CC BY NC (Creative Commons Attribution Non-Commercial) 4.0 licence.
Achieving transparency
Transparency is a collective effort, not just an individual responsibility. Stakeholders across the research lifecycle must work in synchrony to create an environment in which transparency is encouraged and expected, enhancing credibility, reproducibility and public trust in pharmacoepidemiology research.
For researchers, this means adopting structured workflows, clearly documenting study decisions, and explicitly communicating the principles used during their research. Journals and publishers can drive adoption of the statement by requiring authors to report on preregistration, protocol availability and data access. Journals could also award Open Science Badges to publications that include appropriate disclosures. Regulatory bodies and funders can reinforce transparency by advocating for protocol registration based on the HARmonized Protocol Template to Enhance Reproducibility (HARPER).3 Research societies such as the International Society for Pharmacoepidemiology (ISPE) and The Professional Society for Health Economics and Outcomes Research (ISPOR) support these efforts through the Open Science Framework Real World Evidence Registry, enabling secure sharing of protocols, code and methods, even when data sharing is restricted.
Looking ahead
Improving transparency does not have to be about mandates from policymakers or journals; it requires a collective cultural shift in which researchers, institutions, funders, publishers and others contribute to strengthening the foundation of evidence that informs healthcare decisions.
We encourage all stakeholders to embrace the transparency statement, and we welcome your thoughts on how we can further improve transparency in our field.
We are very much hoping to connect with anyone who would like to contribute to this agenda, and those who have comments on or suggestions for our work. Please reach out to us on LinkedIn (Anton Pottegård: https://www.linkedin.com/in/pottegard/; Shirley V Wang: https://www.linkedin.com/in/shirleywang-bwh-harvard/.
References
- Wang SV, Pottegård A. Building transparency and reproducibility into the practice of pharmacoepidemiology and outcomes research. Am J Epidemiol 2024;193:1625–31. https://doi.org/10.1093/aje/kwae087.
- Kildegaard H, Lund LC, Højlund M et al. Risk of adverse events after covid-19 in Danish children and adolescents and effectiveness of BNT162b2 in adolescents: cohort study. BMJ. 2022;377:e068898. https://doi.org/10.1136/bmj-2021-068898.
- Wang SV, Pottegård A, Crown W et al. HARmonized Protocol Template to Enhance Reproducibility of hypothesis evaluating real-world evidence studies on treatment effects: a good practices report of a joint ISPE/ISPOR task force. Pharmacoepidemiol Drug Saf 2023;32:44–55. https://doi.org/10.1002/pds.5507.
The views expressed in this blog post are those of the authors and do not necessarily reflect those of Open Pharma or its Members and Supporters.
Shirley Wang is an Associate Professor at Brigham and Women’s Hospital, Harvard Medical School, where she leads the meta-research in pharmacoepidemiology programmes. Her recent projects include the Reproducible Evidence: Practices to Enhance and Achieve Transparency (REPEAT) programme and the RCT-DUPLICATE project.
Anton Pottegård is a pharmacoepidemiologist and Professor at the University of Southern Denmark. He leads a team of more than 40 researchers and his research focuses on the use of drugs in the broadest sense.
