Waiting Times for Health Services

Annex A. Identifying good practices to measure waiting times

The measurement of waiting times varies widely across OECD countries, from no measurement in countries where this is not perceived to be an important policy issue to sophisticated and comprehensive measurement in some countries where this is considered to be a high priority. This annex provides an overview of different measures of waiting times and identifies good practices.

The two most common measures are waiting times of patients treated and waiting times of patients on the list

An important aspect in measurement relates to the distinction between two distributions of waiting times: i) the distribution of waiting times of patients treated in a given period (for example, a financial year, a quarter or a month); ii) the distribution of waiting times of the patients still on the list at a point in time (a census date, e.g. first Monday of the month or 31^st of December). The first distribution measures the full duration of the patient’s waiting time experience (from entering to exiting the list). The second distribution relates to an “incomplete” waiting time measure since the patient’s wait has yet to come to an end (they are still on the list).

The waiting time of patients treated has the advantage of capturing the full duration of a patient’s journey, but is retrospective in nature. The main advantage of the waiting time of patients on the list is that it captures the experience of the patients who are still waiting at a point in time and can give ‘live’ updates. However, the distribution of the waiting time of the patient on the list oversamples patients with long waiting times, while patients with short duration disappear more quickly from the list. As a result, the mean or median waiting time of patients on the list is not necessarily lower than the waiting time of patients treated, as one may intuitively expect.

Another difference between the two distributions is that the wait on the list includes not only patients who will receive treatment at some point in the future but also those who will not, namely patients who give up the treatment while waiting, die or receive treatment by another provider. These may increase the waiting time of the patients on the list if the waiting list records are not updated regularly.

England is one country that reports both the waiting time of the patients on the list and the waiting time of the patients treated, where waiting time is based on a comprehensive referral-to-treatment (RTT) approach that distinguishes patients who were admitted to hospital from those who were not admitted. The following table covers the twelve-months period from August 2018 and July 2019 and illustrates how the median waiting time can differ across measures.

Table A A.1. Referral to Treatment (RTT) Waiting Times, England

Month	Incomplete RTT pathways	Admitted RTT pathways	Non-Admitted RTT pathways
Median wait (weeks)	Median wait (weeks)	Median wait (weeks)
Aug-18	7.5	9.7	5.8
Sep-18	7.6	10.4	6.5
Oct-18	7.0	10.4	6.1
Nov-18	6.9	10.0	6.0
Dec-18	7.6	9.2	5.6
Jan-19	7.8	10.7	6.7
Feb-19	6.7	10.8	5.8
Mar-19	6.9	10.3	5.6
Apr-19	7.2	10.0	5.8
May-19	7.7	10.3	6.3
Jun-19	7.5	10.6	6.2
Jul-19	7.3	10.2	6.1
Aug-18	7.5	9.7	5.8
Sep-18	7.6	10.4	6.5

Source: NHS England and NHS Improvement: monthly RTT data collection https://www.england.nhs.uk/statistics/statistical-work-areas/rtt-waiting-times/rtt-data-2019-20/.

Comprehensive measures of waiting times are more informative than more partial measures

There are different possible start and end points to waiting times, as shown in Table A A.1 above. The waiting time can be recorded from the GP referral or following a specialist visit. It can end with a surgery or medical treatment, or with a specialist visit. Some health systems measure what is sometimes referred to as the “outpatient” waiting time (from GP referral to specialist visit), others the “inpatient” waiting time (from specialist decision to add the patient on the list to treatment), yet others measure the overall referral-to-treatment waiting time (from GP referral to treatment), as is the case in Denmark, Norway and England.1

Capturing the distribution of waiting times of patients treated or on the list

The most common statistics to measure the waiting times of patients treated or on the list are: the mean waiting time, the median waiting time or the waiting time at other percentiles of the distribution, for example the 75th, or 95th percentile. Many countries also report the number or proportion of patients waiting more than a threshold waiting time (for example 3, 6 or 12 months).

The distribution of waiting times is generally skewed, with a small proportion of patients waiting a very long time. Hence, the mean can be substantially longer than the median. Although the mean and median are representative of the average patient’s experience, measures that focus on the tail of the distribution help to identify those patients whose wait is longest, though as long as prioritisation works well, these patients are also likely to be patients with the lowest need or severity.

Administrative databases can provide more specific and regular data, but population-based surveys can also provide some useful additional information from the patient perspective

Most information on waiting times is available from administrative databases in countries where waiting times are considered to be a significant policy issue. Survey data is also available for a subset of countries (e.g. Australia, as well as other countries participating in the Commonwealth Fund International Health Policy Survey). While administrative databases can provide more regular and reliable data on waiting times for specific health services by region and by setting (e.g. at the hospital or general practice level), surveys can also provide useful complementary information as experienced by patients and some indication of possible inequalities in waiting times by gender, age and socioeconomic status (e.g. by income level), particularly if the sample size is large enough (though in some countries, in particular the Nordic countries, this is also possible with administrative data).

Note

← 1.  Along the pathway patients may need a diagnostic test (e.g. an MRI or CT scan). Therefore, some health systems may record the waiting time from GP referral to a diagnostic test or from specialist request to diagnostic test, and this may or may not be included in the inpatient waiting time.