The data on this website is presented in two different ways. On some pages, you will see an average wait time for a certain test. On other pages, you will see a wait time for a treatment in a chart with percentage signs. Below are definitions that should help you better understand the wait times you are viewing.
Statistical Dictionary
Average wait time: The average (or mean) is the length of time a patient waited to have their test or treatment.
It is calculated by adding together the number of days each patient waited (30 + 10 + 50 + 6 = 96) and dividing by the total number of patients (4) who waited. The average in this example is calculated 96 ÷ 4 = 24 days. The average may be influenced by a few patients who had extremely short or long waits.
Median wait time: The median is the mid point at which patients had their treatment or test done.
It is middle value of the number of days waited arranged in increasing order. For example, if five patients needing a CT scan waited for 5, 10, 30, 45, and 50 days, the median is 30 days. The median is another way of reflecting what a “typical” patient might have experienced in that period and unlike the average wait time, it not influenced by one or two very unusual cases and is therefore more stable.
Percentage Distribution (75% completed within): This table shows patients the percent of people who are being seen or treated in order from the shortest to the longest within a certain number of days.
The percentages are added from the left of the table to the right until 100% is reached. For example, in the table below, 50% of the patients had a CT scan in 5 days or less, an additional 25% of the patients had a CT scan between 6 to 10 days making the number 75% and 100 % of the patients had their CT Scan within 15 days.
| District Health Authorities | 15 Days | 30 Days | 60 Days | 90 Days |
|---|---|---|---|---|
| Facility A | 10% | 25% | 75% | 100% |
| Facility B | 10% | 25% | 75% | 100% |
Prospective Wait Times: This wait time measures how long people will wait before they will receive health care services.
Wait times for MRI are measured prospectively by counting the number of calendar days from the day the request arrives in the diagnostic imaging department to the next available day with three open appointments.
Retrospective Wait Times: This wait measures how long people have waited for health care treatment.
For example, wait times for hip replacements are measured by counting the number of calendar days from the date the specialist and patient decided the service was medically necessary to the date the service was performed.
Source: With some adapted from Ontario Wait Times Website