What are the main risk factors affecting a study timeline?
In clinical research, a timeline is not just a list of dates — it is a dynamic operational plan that requires realistic assumptions, careful oversight and flexibility.
From our experience with hundreds of projects at Biostat®, we know that most delays stem not from scientific issues but from underestimated operational and organisational factors.
Below are the most common risks that significantly impact the duration and flow of clinical studies.
Key Risk Factors
1. Unrealistic scheduling
Overly optimistic or oversimplified timelines are a leading cause of delays. This includes underestimating the time needed for Bioethics Committee and URPL approvals, site activation, patient recruitment, database lock and preparation of the final report.
At Biostat®, we build timelines based on realistic scenarios and include time buffers for critical steps.
2. Patient recruitment challenges
Recruitment is the most difficult and commonly underestimated component of any study. Issues may arise from limited patient availability, overly strict eligibility criteria, competing studies or insufficient site motivation.
Often, planned recruitment numbers are simply unachievable. This is why we perform a feasibility study before the project starts to verify real recruitment potential.
3. Selecting the wrong study sites
Choosing sites with limited experience, inadequate infrastructure or insufficient patient pools often results in poor recruitment performance.
Biostat® works with a wide network of verified sites and evaluates their capabilities before contracts are signed.
4. Unexpected disruptions at study sites
Staff turnover, shortages, reorganisations or temporary shutdowns (e.g., due to pandemics or renovations) can completely disrupt the timeline.
Regular contact with sites and flexible monitoring help minimise such impacts.
5. Regulatory and ethical challenges
Approval processes may be prolonged due to additional queries or amendments. Delays also occur when a project is incorrectly classified (e.g., clinical investigation vs. observational study).
Therefore, we map regulatory requirements for every project and review documentation for compliance with current laws.
6. Logistical and technological issues
Supply delays (investigational products, materials, medical devices) and system issues (eCRF, IWRS, eTMF) can significantly slow down study progress.
Biostat® relies on proven in-house IT tools and performs integration tests before recruitment begins.
7. Participant safety events
Unexpected adverse events may require protocol amendments, dose adjustments or temporary study holds.
Every project must have rapid response procedures included in the Risk Management Plan.
8. External and macroeconomic factors
Global disruptions — such as pandemics, wars, supply chain issues, legal changes or inflation — can impact study timelines and costs.
We therefore build schedules with awareness of potential “critical points” requiring adjustments.
How we minimise risks
At Biostat®, we create a project-specific risk map (Risk Assessment) and a detailed Risk Management Plan (RMP) during the planning phase.
This document identifies potential risks, assigns priorities and defines preventive or corrective actions.
We monitor these risks throughout the entire study lifecycle and update the plan as needed.
This ensures studies remain stable, controlled and on schedule, even in changing conditions.
Sponsors benefit from predictable timelines and costs, while sites can focus on what matters most: patient safety and data quality.
