Data collection

This section contains the following:

Introduction
Things to consider
Illustrative example
Additional resources
Further reading

Introduction

Data collection (the measurement and recording of source data), is considered to be the most crucial stage of the data management process. Errors made at this stage can be the most difficult to detect and to correct compared to those made at a later data management stage.

The first stage in designing the data collection strategy for a trial is to decide what data will be collected and at what time points. These decisions should be driven by the scientific objectives of the research and care should be taken to only collect data that are needed to meet the objectives. Investigators should keep the amount of data collected per participant to a minimum by referring to dummy tables (see Dummy tables).

Once it has been decided which data to collect, the investigator must choose how to collect the data. This may be by questionnaire, face-to-face interview, case note review, focus group, electronic record systems or through routinely collected data. Investigators should be aware of Data Protection legislation in their own country.

Things to consider

Follow the decisions on what data to collect and at what time points from the protocol.
Outline how issues such as: questionnaire administration; collection of biological samples, personnel and training requirements; transmission of data to co-ordinating centre; and confidentiality and security will be handled.
A schedule of patient visits and description of what will be done at each visit (e.g. which questionnaires are to be completed and which lab procedures are to be carried out) should be in the data management manual.
In each center ultimate responsibility for Data Protection issues should be delegated to one person.
Train data collectors and supervisors
Translation of data forms

Illustrative example - using electronic data collection (audio)

The Practical Approach to Lung Health in South Africa (PALSA) initiative is a local adaptation and expansion of the World Health Organisation’s (WHO) Practical Approach to Lung Health (PAL) strategy. PALSA aims to strengthen the health system through the implementation of locally applicable integrated symptom- and sign-based (syndromic) algorithms for the detection and management of respiratory disease conditions in primary care availability of more diagnostic resources and treatments. The PALSA trial used PDAs to collect data in the field. Merrick Zwarenstein, Centre for Health Services Sciences, Sunnybrook Hospital, Toronto, Canada, explains how electronic data collection was done in the PALSA trial. (MP4, 6 minutes 3 seconds) Can't see video controller? Play it in your media player.

Additional resources

Checklist for data collection

This checklist has been contributed by Barbara Farrell who prepared it for the third version of the Trial Management Guide.

Checklist for implications of Data Protection

This checklist was a modified version of one developed by Barbara Farrell who prepared it for the third version of the Trial Managers Guide.

Bheekie A, Buskens I, Allen S, et al. The Practical Approach to Lung Health in South Africa (PALSA) intervention: respiratory guideline implementation for nurse trainers. International Nursing Review 2006;53:261-268.

Hosking JD, Newhouse MM, Bagniewska A, et al. Data collection and transcription. Controlled Clinical Trials 1995;16:66S–103S.

Knatterud GL, Foreman SA, Canner PL: Design of data forms. Controlled Clinical Trials 1983;4:423-440

Hilner JE, McDonald A, Van Horn L, et al. Quality control of dietary data collection in the CARDIA study. Controlled Clinical Trials 1992;13:156–169.

Spilker B, Schoenfelder J: Data collection forms in clinical trials. New York, Raven Press, 1991

Pocock SJ. Clinical Trials: A Practical Approach. John Wiley and Sons, Chichester, 1983.

Duley L and Farrell B. Clinical Trials. London: BMJ Books, 2002.