Table 6

OLS with HHI per quality aspect with relevant years 2006/2007/2009(#) or 2007/2009

Coefficient of combined quality aspects


Quality aspects 1-3# ****

-5.42 10-6 ***

Quality aspects 4-12

-4.89 10-6 ***

*Significant at p < 0.05, **significant at p < 0.01, ***significant at p < 0.001 **** Given the skewed distribution of the error term we estimated confidence intervals we applied a non parametric bootstrap procedure with 10,000 replications and hospital stratified sampling. Confidence intervals were based on bias corrected percentile score and the reported coefficients are within these confidence intervals, meaning that the found coefficients are significant. For additional analysis regarding potential outliers that may have influenced our regression results, please see Additional file 1. This analysis shows that this is not the case.

Ikkersheim and Koolman BMC Health Services Research 2012 12:76   doi:10.1186/1472-6963-12-76

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