The study protocol is the blueprint that all researchers will follow.
A study protocol is a document that describes, in detail, the plan for conducting the clinical study. The study protocol explains the purpose and function of the study as well as how to carry it out. Some specific things included in the protocol are the reason for the study, the number of participants, eligibility and exclusion criteria, details of the intervention or therapy the participants will receive (such as frequency and dosages), what data will be gathered, what demographic information about the participants will be gathered, steps for clinical caregivers to carry out, and the study endpoints. A single standard protocol must be used without deviation to ensure that the resulting data will be significant and reliable.
The NICHD expects that each study protocol will include a monitoring plan that defines:
- How the study will comply with regulatory requirements
- The specific events and activities that will be monitored during the study
- The roles and responsibilities for everyone on the team who is involved in monitoring
- Who has responsibility for reporting (and who they report to)
- A schedule for monitoring
- The timing or number of events that would lead to a stop in study accrual, an assessment of eligibility, monitoring, intervention, and under what conditions study accrual would resume
Defining the study design for the protocol
Protocols may outline one of several different types of study designs, some which are described below, that investigators may follow:
- Case Study: This type of study relies on a literature review or uses a physician’s clinical cases to introduce a clinical abnormality, usually something rare, new, or something that presents in an unusual way.
- Case-Control Study: This study compares the number of people who had a potential risk factor in the case group (those with the disease) with those who had the same potential risk factor in the control group (those without the disease). This type of study demonstrates association, but not cause and effect.
- Cohort Study: Much like a case-control study, this type of study tracks and compares risk factors shared between the case group and the control group. This type of study can be prospective (following participants as time moves forward) or retrospective (looking back at events that have already happened to participants). This type of study also demonstrates association, but not cause and effect.
- Randomized Controlled Trial (RCT): In this type of study, participants are randomly assigned, using a computer or matrix, into the control group or the investigational group. The control group receives the typically used or approved treatment; the investigational group receives the treatment or intervention being studied. This study type is generally considered the most rigorous study design.
- Blind and Double-Blind Studies: When a study is "blinded," participants do not know which group they are randomly assigned to. A double-blind study means that neither the study personnel who interact with participants, nor the participants know who is assigned to which group. Another variation of this design is called a "double-dummy" study, meaning participants receive a mixture of active and inactive product. These study designs are meant to eliminate possible bias by the participant or caregiver toward or against a therapy or a placebo. Some study personnel who don't interact with the participants keep track of who is in which group.
- Meta-analysis: This type of study involves analysis of multiple similar studies (already completed) that is performed according to a protocol that outlines the methodology to be used.
Resources for designing a protocol for a study
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