Your Easy Guide to Clinical Studies

The planning of data collection include the:

• Definition of all variables that need to be collected in the study in order to answer the research question
• Timing of when, which variables (data) must be collected during study conduct (i.e. which variable do I need to collect at baseline, visit 1, 2 …, end of study)
• Methods used for data collection (e.g. blood draw, participant questionnaires, interview regarding medical history, x-rays)

 

Type of study variables include:

• Primary outcome(s) (also referred to as endpoint(s)): Considered the most important variable of interest
• Secondary outcomes: Additional variables monitored during study conduct
• Safety outcome : Negative events experienced by study participants
• Other outcomes: Variables that do not fit the above classifications
• Predictor variable: Can potentially affect study outcome(s) variables
• Confounding variable: May lead to the misinterpretation of study results
• Population variables: Describe the study population

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As a SP-INV:

• Decide which variables are needed to answer your study question
• Consult with a statistician to ensure study variables are correctly defined and available for the statistical analysis of your study (i.e. outcome -, predictor - , confounding -, population descriptive variables)  
• Consult with a data manager to ensure the complete and correct documentation of your study data (e.g. important information is not missed)

 

When planning data collection, establish procedures to ensure ongoing data quality (e.g. SOPs, WIs). This will guarantee that data is correct and complete.

 

Aspects include:

• To have an appropriate study design, where study visits occur at the time when study data (i.e. outcome variable(s)) must be collected and assessed
• The availability of resources needed to measure and document study outcome(s) (e.g. CT scan, radiologists diagnosing scans) 
• The availability of study staff trained on data collection and documentation (e.g. how to enter data in the study database)

References

ICH Topic E9 – see in particular

• 2.1.1 Development Plan
• 2.2.1 Population
• 2.2.2 Primary and Secondary variables
• 2.2.5 Multiple primary variables
• 2.2.6 Surrogate Variables