Quality control

This section contains the following:


Introduction

The success of any clinical trial depends on the quality of the data collected.  Ensuring good quality data requires developing extensive and detailed quality assurance procedures such as those for monitoring the clinical centres; and those for assuring quality of data handling and processing in the coordinating centre.  As in all aspects of clinical trials, a quality control program requires attention to detail and careful planning.  This program should include plans for data checking (how much will be checked by whom, and by what method); audit trails (detailed log showing which data have been changed, the reason for any change, who made the change and when); and source verification procedures (how much data will be checked against source document).  There should be a written description of the quality control program within the Manual of Operations.  

During the planning of data collection and management, a number of decisions must be made regarding quality assurance procedures, here are some questions you might like to think about:



Back to top


Things to consider when writing a protocol


Back to top


Illustrative example - Perinatal care trial

Consistency checks are performed during data entry and warnings are displayed.  The data is checked to make certain that entered values are acceptable, that all required fields are entered, and that items are consistent with other related items in the database.  After completion of the data entry procedure, the system generates Validation Reports (VRs) that must be resolved by the data manager.  When resolving VRs, a record of the database update will be kept, identifying information about the person who made the update, the date, changed values, and comments. Reports detailing the status of data collection and validation are available. 

(CLAP Trial - go to protocol)


Back to top    


Additional resources

PSt resource icon Checklist for data checks

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


Back to top


PSt resource icon Checklist for double data entry

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


Back to top


Trial Protocol Tool resource icon Checklist for missing and inconsistent data

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


Back to top



Further reading

Neaton JD, Duchene AG, Svendsen KH, et al. An examination of the efficiency of some quality assurance methods commonly employed in clinical trials. Statistics in  Medicine 1990;9:115–124

Williams OD. A framework for the quality assurance of clinical data. Clinical Pharmacology and therapeutics 1979: 24; 700-702

Knatterud GL. Methods of quality control and of continuous audit procedures for controlled clinical trials. Controlled clinical trials 1981:1;327-332

Hosking JD, Rochon J. A comparison of techniques for detecting and preventing key-field errors. American Statistical Association, 1982, pp 82-87

Mullooly JP. The effects of data entry errors: an analysis of partial verification. Computational Biomedical research 1990; 23: 259-267

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

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


Back to top     

This page was last updated 18th April 2005.