Exploring the degree of concordance of coded and textual data in answeringclinical queries from a clinical data repository

Objective: To query a clinical data repository (CDR) for answers to clinica l questions to determine whether different types of fields (coded and free text) would yield confirmatory complementary or conflicting information and to discuss the issues involved in producing the discrepancies between the fields. Methods: The appropriate data fields in a subset of a CDR (5,135 patient re cords) were searched for the answers to three questions related to surgical procedures. Each search included at least one coded data field and at leas t one free-text field. The identified free-text records were then searched manually to ensure correct interpretation, The fields were then compared to determine whether they agreed with each other, were supportive of each oth er, contained no entry (absence of data), or were contradictory. Results: The degree of concordance varied greatly according to the field an d the question asked. Some fields were not granular enough to answer the qu estion. The free-text fields often gave an answer that was not definitive. Absence of data was most logically interpreted in some cases as lack of com pletion of data and in others as a negative answer. Even with a question as specific as which side a hernia was on contradictory data were found in 5 to 8 percent of the records Conclusions: Using the data in the CDR to answer clinical questions can yie ld significantly disparate results depending on the question and which data fields are searched. A database cannot just be queried in automated fashio n and the results reported. both coded and textual fields must be searched to obtain the fullest assessment. This can be expected to result, in inform ation that may be confirmatory, complementary, or conflicting. To yield the most accurate information possible, final answers to questions require hum an judgment and may require the gathering of additional information.