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Table 6 Robustness check with fractional logit models and aesthetic invasive treatments

From: Is there a volume-quality relationship within the independent treatment centre sector? A longitudinal analysis

 Model IModel IIModel III
Type of outcome variableProportional postoperative infectionsProportional postoperative infectionsPercentage postoperative infections – aesthetic surgery
Type of model usedFractional logitFractional logitRE-Linear
Type of data usedAnnual dataAnnual dataAnnual data
Log invasive treatments−0.226** (0.111) −0.566*** (0.135)
Highest quantile invasive treatments Reference 
Higher medium quantile invasive treatments 0.279 (0.193) 
Lower medium quantile invasive treatments 0.869*** (0.236) 
Lowest quantile invasive treatments 1.321*** (0.452) 
FTE number of professionals0.029 (0.021)0.056*** (0.021)0.012 (0.033)
No chain membershipReferenceReferenceReference
Chain membership−0.188 (0.215)−0.550* (0.318)0.755** (0.317)
For-profitReferenceReferenceReference
Non-profit0.558* (0.310)0.782** (0.339)−0.226 (0.319)
Cluster/IdentifierID ITCID ITCID ITC
Observations555596113
  1. Corrected for case-mix (ASA II & III), type of treatment (except Model III since it only includes aesthetic surgery) and year
  2. ****p < 0.01, **p < 0.05, *p < 0.1