Factsheet: Short stay emergency department events

Events where admitted patients are discharged under an emergency department specialty after a length of stay of less than two days.

Published online: 
30 June 2015

This factsheet is targeted at users of hospital data from the National Minimum Dataset (NMDS).

When looking at data from the NMDS, such as hospitalisations for certain diagnoses, it is important to consider short stay emergency department events. From July 1999 to June 2012, DHBs had differing admission practices, which resulted in differences in the data reported. From 1 July 2012, all DHBs were reporting short stay emergency department events consistently. Therefore excluding these events from analyses of hospital data for the years prior to 2012/13 is recommended.

It is evident from the figure below that short stay emergency department events were reported inconsistently over time and by different DHBs. By excluding the data that is inconsistently reported, the remaining data can be used to make meaningful comparisons across years and DHBs. This exclusion method is used in the analysis of intentional self-harm hospitalisations in the annual Suicide Facts publication. The method of exclusion is described further in the notes below.

Figure 1: Comparing the number of short stay emergency department events for four example DHBs, 1995/96–2012/13

For one example DHB, the number of recorded events was very low until 1999/00, when the numbers went up by an order of magnitude, and were then quite variable from year to year. For another, data wasn't collected until 1999/00. It was quite variable after that. Another DHB didn't start collecting data till 2007/08. Another had collected data since 1996/97, with very consistent numbers for the most part.

Note: refer to the accompanying tables for data for all DHBs.
Source: National Minimum Dataset

Excluding short stay emergency department events has different effects on the data depending on the cause of the hospitalisation.

For example, there was greater variation in short stay emergency department reporting for intentional self-harm hospitalisations compared to asthma hospitalisations from 2000/01 to 2012/13 (Figure 2). It is important to bear this in mind when analysing hospital information.

Figure 2: Comparison of short stay emergency department hospitalisations by certain causes, 2000/01–2012/13

Asthma hospitalisations show a fairly consistent difference between all asthma hospitalisations and hospitalisations excluding SSED events. Motor vechicle traffic accidents shows more variation in the total hospitalisations compared to those excluding SSED. Epilepsy hospitalisations show a fairly consistent difference. For intential self-harm, there is quite a lot of variation in the difference.

Note: SSED events are short stay emergency department events
Source: National Minimum Dataset


This factsheet was published in June 2015.

The Ministry of Health defines short stay emergency department events as any hospital discharge where both:

  • length of stay is zero or one midnight spent in hospital
  • health specialty code is M05, M06, M07 or M08.

Further information on health specialty codes can be found in the health specialty code table.

Hospitalisations represent individual events rather than individual people; that is, a single person can contribute multiple unique events to the data set.

The Ministry is endeavouring to address inconsistencies in the collection of short stay emergency department data, however filtering cannot completely eliminate differences caused by different methods of managing patients and keeping records.

For further information contact:

Postal address: Analytical Services
Ministry of Health
PO Box 5013
Wellington 6145
New Zealand
Email: [email protected]
Phone: (04) 496 2000

Publishing information

  • Date of publication:
    30 June 2015
  • Citation:
    Ministry of Health. 2015. Factsheet: Short stay emergency department events. Wellington: Ministry of Health.
  • Ordering information:
    Only soft copy available to download
  • Copyright status:

    Owned by the Ministry of Health and licensed for reuse under a Creative Commons Attribution 4.0 International Licence.

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