Comparison of electronic data capture (EDC) with the standard data capture method for clinical trial data

Abstract

Background: Traditionally, clinical research studies rely on collecting data with case report forms, which are subsequently entered into a database to create electronic records. Although well established, this method is time-consuming and error-prone. This study compares four electronic data capture (EDC) methods with the conventional approach with respect to duration of data capture and accuracy. It was performed in a West African setting, where clinical trials involve data collection from urban, rural and often remote locations.

Methodology/principal findings: Three types of commonly available EDC tools were assessed in face-to-face interviews; netbook, PDA, and tablet PC. EDC performance during telephone interviews via mobile phone was evaluated as a fourth method. The Graeco Latin square study design allowed comparison of all four methods to standard paper-based recording followed by data double entry while controlling simultaneously for possible confounding factors such as interview order, interviewer and interviewee. Over a study period of three weeks the error rates decreased considerably for all EDC methods. In the last week of the study the data accuracy for the netbook (5.1%, CI95%: 3.5-7.2%) and the tablet PC (5.2%, CI95%: 3.7-7.4%) was not significantly different from the accuracy of the conventional paper-based method (3.6%, CI95%: 2.2-5.5%), but error rates for the PDA (7.9%, CI95%: 6.0-10.5%) and telephone (6.3%, CI95% 4.6-8.6%) remained significantly higher. While EDC-interviews take slightly longer, data become readily available after download, making EDC more time effective. Free text and date fields were associated with higher error rates than numerical, single select and skip fields.

Conclusions: EDC solutions have the potential to produce similar data accuracy compared to paper-based methods. Given the considerable reduction in the time from data collection to database lock, EDC holds the promise to reduce research-associated costs. However, the successful implementation of EDC requires adjustment of work processes and reallocation of resources.

Figure 1. Error rates (%) per questionnaire.

The graph above presents the error rates (%) per interview for the standard paper-based data collection method and the four electronic data capture methods; netbook, tablet PC, PDA, and telephone interview in combination with EDC, in the 1^st, 2^nd, and 3^rd study week. The bars represent median error rates per method and week.

Figure 2. Error rate (%).

The overall error rates per 100 fields (%) and 95% confidence Intervals (Wilson) for the standard paper-based as well as the electronic data capturing methods in the first, second and third week of the study (1st week: blue, 2nd week: red, and 3rd week: green) are presented in graph A. The five smaller graphs present the error rate by field type and study week (B: text fields, C: date, D: single select, E: numerical, F: skip).

Figure 3. Missing values.

The overall error rate (%) was defined as error per 100 fields and included the missing values. In the graph above the overall error rate is split into error rate, defined as incorrect entries per 100 fields (white), and missing rate, defined as missing values per 100 fields (black). The missing rates for the 1st, 2nd and 3rd week are presented in the three smaller graphs.

Figure 4. Duration of data entry per questionnaire.

The figure presents the time (min) a data entry clerk needed to transcribe the data from one paper Case Report Form to an electronic record. The median time is represented by a red line.