[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Epidemiology](https://durgical.com/en/epidemiology/) › [Research methods](https://durgical.com/en/epidemiology/areas/research/) › The research protocol # The research protocol - Concept The written plan of a study: what is asked, how, with whom, when and with what resources. It is approved and registered before the start. Updated Nov 13, 2026 ## Key points - Core sections: title, background and rationale, question and objectives, hypothesis, design, population and sample, variables, data collection, analysis, ethics, timeline, budget and dissemination. - Clinical trials are registered before the first participant is enrolled (the WHO ICTRP platform and its primary registries). - SPIRIT is the guideline for the items a clinical trial protocol should contain. - The team: principal investigator, co-investigators, field coordinator, statistician and data manager, each with written duties. - Protocol amendments are dated, justified and approved again by the ethics committee. On this page - The basics Key points - What it is - Key facts - Worked example - Protocol sections and the question each one answers - Markers - In practice - Common pitfalls - Memory aid - Elsewhere in DurgiPedia - Study Test yourself - Connections Connections ## What it is The protocol is the document that describes, before the first datum is collected, everything the study will do: the question, the design, the population, the variables, the analysis, the ethical aspects, the timeline and the budget. It applies the scientific method (observation, question, hypothesis, test and conclusion) to a concrete plan. The ethics committee reviews it; clinical trials are publicly registered before the first participant is enrolled, and later changes are documented. ## Key facts - Research process: idea → literature search → question → protocol → ethics approval and registration → pilot → data collection → analysis → publication. - Recruitment time = participants needed / (sites × enrolments per site per month). ## Worked example - Data: a 2-site trial needs 300 participants; each site enrols 10 a month and each person is followed for 3 months. - Combined rate: 2 × 10 = 20 a month. Months of recruitment: 300 / 20 = 15. - Before recruitment: 3 months for the ethics committee, trial registration and staff training. - Recruitment ends in month 3 + 15 = 18; the last person enrolled finishes follow-up 3 months later, in month 21. - Cleaning, analysis and report: 3 months. Total length: 3 + 15 + 3 + 3 = 24 months. - If each site enrols only 7 a month: 300 / 14 = 21.4, rounded up to 22 months; total 3 + 22 + 3 + 3 = 31 months. - Reading: a recruitment rate 30 % lower lengthens the study by 7 months; the protocol timeline must rest on real figures from each site. ## Protocol sections and the question each one answers | Section | What it answers | | --- | --- | | Background and rationale | What is known, and why is this study needed? | | Question, objectives and hypothesis | What exactly do we want to know? | | Design | Which type of study answers it best? | | Population, criteria and sample | With whom, and how many? | | Variables and measurements | What is measured, and how? | | Analysis plan | How will the data answer the question? | | Ethical aspects | How are participants protected? | | Timeline and budget | When, and with what resources? | ## Markers - SPIRIT - ICTRP - REC ## In practice - In Colombia the protocol goes to the institution's research ethics committee, under Resolución 8430 de 1993 (see Ethics). - Journals require clinical trials to have been registered before they started in order to consider them for publication. - Publishing or registering the protocol lets readers compare what was planned with what was reported. ## Common pitfalls - Writing the protocol after the data have been collected. - Timelines based on optimistic recruitment rates that nobody checked. - Changing the primary outcome without an amendment or a reason. ## Memory aid ‘If it is not in the protocol, it was not planned’: the protocol is the study's contract with itself. ## Test yourself Think of the answer, then tap the question to see it. ## When must a clinical trial be registered? Before the first participant is enrolled, in a registry recognised by the WHO ICTRP platform. ## Which guideline describes the items of a clinical trial protocol? SPIRIT. ## 240 participants are needed and 3 sites enrol 5 a month each. How many months of recruitment? 3 × 5 = 15 a month; 240 / 15 = 16 months. ## What is done if the protocol must change during the study? A dated, justified amendment, approved by the ethics committee and recorded in the registry. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/epidemiology/the-research-protocol/) ## Elsewhere in DurgiPedia - [Research ethics committees](https://durgical.com/en/medical-ethics/research-ethics-committees/) - [Resolution 8430 of 1993: health research in Colombia and its risk categories](https://durgical.com/en/medical-ethics/resolution-8430-of-1993-health-research-in-colombia-and-its-risk-categories/) ## Connections ## Related 6 - [The research question and objective](https://durgical.com/en/epidemiology/the-research-question-and-objective/) - [Statistical analysis plan](https://durgical.com/en/epidemiology/statistical-analysis-plan/) - [Study management and data quality](https://durgical.com/en/epidemiology/study-management-and-data-quality/) - [Reporting guidelines: CONSORT, STROBE, PRISMA, STARD](https://durgical.com/en/epidemiology/reporting-guidelines-consort-strobe-prisma-stard/) - [Applying for research funding](https://durgical.com/en/epidemiology/applying-for-research-funding/) - [Sample size](https://durgical.com/en/epidemiology/sample-size/) [← All of epidemiology](https://durgical.com/en/epidemiology/) Educational content on epidemiological and statistical methods; the examples use made-up numbers to teach the calculation. Not a clinical or legal guide: current Colombian rules are in the official sources. Sources: [SPIRIT 2025 Statement: Defining standard protocol items for clinical trials](https://www.equator-network.org/reporting-guidelines/spirit/) (EQUATOR Network, 2025); [International Clinical Trials Registry Platform (ICTRP)](https://www.who.int/tools/clinical-trials-registry-platform) (World Health Organization, 2026); [E6(R3) Good Clinical Practice (GCP)](https://www.fda.gov/regulatory-information/search-fda-guidance-documents/e6r3-good-clinical-practice-gcp) (U.S. Food and Drug Administration, 2025). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/epidemiology/the-research-protocol/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/epidemiology/the-research-protocol/