Expert Interviews
Leidy Johanna Portela Ramírez is a Clinical Research Associate (CRA) based in Ibagué, Colombia, with strong expertise in epidemiology, clinical trial monitoring, and GCP compliance across areas such as cardiovascular devices and infectious disease prevention.
In the following interview, Leidy shares key reflections on epidemiological study design, bias mitigation, data quality assurance, and ethical compliance—critical elements for ensuring the integrity and success of clinical research.
ABRS: What key criteria do you consider when designing an epidemiological study?
Leidy Portela: When designing an epidemiological study, I begin with a clearly defined research question and specific objectives. Based on these objectives, I select the most appropriate study design—such as a cohort, case-control, or experimental approach. I carefully define the study population, ensure appropriate sampling methods, and use valid and reliable measures for both exposures and outcomes. I also plan strategies to control for confounding and minimize bias.
Ethical considerations are essential throughout, including informed consent, confidentiality, and risk minimization. Additionally, I develop a detailed statistical analysis plan in advance, addressing issues such as missing data, effect modification, and sensitivity analyses. Lastly, I assess the overall feasibility of the study, including timelines and available resources.
ABRS: How do you handle common biases in epidemiological research, and what strategies do you use to minimize them?
Leidy Portela: To address biases in epidemiological research, I take a proactive approach during the study design phase. To reduce selection bias, I ensure representative sampling and apply clear inclusion and exclusion criteria. For information and recall bias, I rely on validated instruments and, when possible, objective data sources.
I manage confounding through design strategies such as matching or restriction and through multivariable analysis during data processing. To address potential loss to follow-up, I implement retention strategies and conduct sensitivity analyses. My overarching approach combines rigorous study design with robust analytical methods to minimize bias and uphold validity.
ABRS: Can you describe your process for ensuring data quality and cleaning before analysis?
Leidy Portela: Ensuring data quality starts with a solid data collection plan, utilizing standardized procedures and validated tools. Once data are collected, I perform initial checks for completeness, consistency, and accuracy—such as identifying missing values, outliers, or logical inconsistencies.
I use descriptive statistics and data visualizations to detect anomalies and to better understand data distributions. For data cleaning, I employ reproducible scripts to handle missing data, correct errors, and standardize variables. All cleaning steps are meticulously documented to ensure transparency and reproducibility. Data quality assurance is an ongoing, iterative process—not a one-time task.
ABRS: Which statistical analysis software do you use most frequently, and why?
Leidy Portela: I primarily use Stata and SPSS, depending on the project’s needs. Stata is especially well-suited for epidemiological analyses and efficient data management, particularly in multicenter or collaborative studies. SPSS, on the other hand, is ideal for routine statistical analyses and is commonly used in clinical environments due to its intuitive interface. My choice of software depends on the study design, data complexity, and the technical expertise of the team involved.
ABRS: How do you ensure ethical compliance and data confidentiality when handling sensitive information?
Leidy Portela: Ethical compliance and data confidentiality are central to responsible clinical research. I adhere to ICH-GCP guidelines, the Declaration of Helsinki, and all relevant local data protection regulations. Before initiating a study, I ensure that ethics committee approvals are secured and that informed consent documents clearly articulate data usage, confidentiality safeguards, and participants’ rights.
I implement data pseudonymization or anonymization protocols and use secure electronic case report forms (eCRFs) with role-based access. Sensitive data are stored and transmitted using encrypted systems. Additionally, I ensure that all team members receive proper training on ethical conduct and data protection procedures to maintain compliance throughout the study lifecycle.
We extend our sincere thanks to Leidy Johanna Portela Ramírez for generously sharing her time, expertise, and perspectives on the essential aspects of epidemiological research. Her insights on study design, bias control, data quality, and ethical compliance offer valuable guidance for professionals committed to advancing clinical research with scientific and operational excellence.