# Multi-Center Healthcare Data Quality Measurement Model and Assessment Using OMOP CDM
## 3 Results
### Multicenter OMOP CDM Data Quality Assessment Results
#### 3.1.2 NDPR and WDPR  
The data quality was examined based on five dimensions and the error rate was evaluated for each dimension. For each error type, the evaluation results were compared using the NDPR, which assessed only the number of errors, and the WDPR, which provided the weight of that type of error.  
When checking the DQ4 HEALTH dimension result, the quality level of the four dimensions was close to 99% or higher. Furthermore, the consistency dimension had the highest error rate, at 70.06% (1,338,817,961 records), of all the error data. As for the results of quality analysis, NDPR, which does not reflect the weight of consistency, was 90.66%, 76.52%, and 78.64% for institutions A, B, and C, respectively. When weights for each dimension evaluated by experts were provided, 98.22%, 94.74%, and 95.05% of institutions A, B, and C, respectively, showed results (Figure 2 and Table 5).  
Depending on whether the experts' weights were reflected, the difference in results was due to the following factors. Experts gave low weight to the consistency dimension in the case of tables that did not affect analysis and medical concepts that are hard to map using standard medical terms.  
We adopted the chi-square analysis method to verify whether there is a level difference according to the quality results of all medical institutions and conducted a subsequent analysis. The result was \(p<0.001\), which confirmed that there was a difference in the quality of data from each hospital.  
Additionally, we performed a chi-square analysis to determine whether there was any difference in quality for each OMOP CDM table at each medical institution. This allowed us to check the factors that affected the overall results. Of the 195 variables, all three medical institutions had no errors. Either that or two medical institutions excluded variables without errors from the analysis and we performed a chi-square analysis on 96 variables. The analysis confirmed that there was a difference in the quality of healthcare data between institutions.  
Consequently, it was confirmed that institution A had the highest quality data of the three medical institutions. Comparatively, institution B possessed low-quality data. Regarding institution B, the error derived from the consistency dimension was the highest of all three institutions. The consistency dimension was confirmed to be a factor with low quality.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Center**} & **DQ4 HEALTH** & **Total Dimension** & **Total Dimension** & **Total Dimensions** & **NDPR** & **WDPR** \\  & **Dimension** & **Data Count** & **Error Count** & **Error Rate** & & **NDPR** & **WDPR** \\ \hline \multirow{4}{*}{A} & Completeness & 5,460,723,980 & 8276 & 0.01\% & 99.99\% & 99.99\% \\  & Validity & 1,360,559,053 & 22,801,212 & 1.67\% & 98.33\% & 99.70\% \\  & Accuracy & 3,570,299,098 & 59,288,628 & 1.66\% & 98.34\% & 99.69\% \\  & Uniqueness & 840,625,891 & 239,985 & 0.03\% & 99.97\% & 99.99\% \\  & Consistency & 5,005,238,125 & 467,936,657 & 9.34\% & 90.66\% & 98.22\% \\ \hline \multirow{4}{*}{B} & Completeness & 2,619,120,230 & 1,399,297 & 0.05\% & 99.95\% & 99.99\% \\  & Validity & 644,669,318 & 11,173,281 & 1.73\% & 98.27\% & 99.69\% \\  & Accuracy & 1,847,001,586 & 333,479 & 0.02\% & 99.98\% & 99.99\% \\  & Uniqueness & 412,280,539 & 0 & 0\% & 100\% & 100 \\  & Consistency & 2,835,935,266 & 816,059,524 & 28.77\% & 71.23\% & 94.74\% \\ \hline \multirow{4}{*}{C} & Completeness & 1,826,576,516 & 1,545,055 & 0.08\% & 99.92\% & 99.98\% \\  & Validity & 430,638,422 & 7,014,267 & 1.62\% & 98.38\% & 99.71\% \\ \cline{1-1}  & Accuracy & 1,270,385,522 & 302,273 & 0.00\% & 99.99\% & 99.99\% \\ \cline{1-1}  & Uniqueness & 291,598,022 & 0 & 0\% & 100\% & 100\% \\ \cline{1-1}  & Consistency & 2,003,506,197 & 522,758,437 & 26.09\% & 73.91\% & 95.05\% \\ \hline \hline \end{tabular}
\end{table}
Table 5: Multicenter OMOF CDM data quality assessment specific results.  
Figure 2: Comparison of NDPR and WDPR by consistency weights.