Date of Award


Degree Type


Degree Name

Master of Science


Epidemiology and Biostatistics


Dr. Bert Chesworth

Second Advisor

Dr. Kathy Speechley

Third Advisor

Dr. Allan Donner


Ontario Ministry of Health and Long-Term Care (MOHLTC) established the Ontario Joint Replacement Registry (OJRR) in April 2000 to provide information needed to assess waiting times for Total Joint Replacement (TJR) surgery on an ongoing basis. Therefore a major concern of the OJRR is the quality of its waiting time data. The primary objective of this study was to determine the quality of the OJRR waiting time data by measuring the bias in these two waiting time periods: referral to surgery and decision to surgery. The mean difference method was used to estimate bias in its waiting times reported as a continuous variable and the McNemar test was used to estimate bias in its waiting times reported as a dichotomous variable. In continuous form, bias in OJRR waiting times was estimated as a relatively small point estimate (i.e. 0.13 and 0.66 weeks for decision and referral to surgery, respectively); but with considerable variability associated with these values (i.e. +/- half a year). As a binary variable, indicating if surgery was received within a waiting time threshold, no bias was found. Our results suggested that better definitions for waiting time date fields, especially for decision date and referral date fields, may be in order.



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