Winter sitreps: who, when and what

For the past six years’ NHS England have published weekly winter sitreps; giving us timely insight into the performance of NHS acute care providers over the winter period. Usually, performance data comes out only once a month or quarter, so this gives us the best evidence-based view of the day to day frontline pressures in the NHS at any time of the year. However each year there are slight variations in which data is published, for how long, and in what format. So how does the 2017/18 data compare?

The first, and arguably the most important, thing to say about the winter sitrep data is that it’s only a partial picture. The 2017/18 sitreps report data for the 137 NHS foundation trusts and trusts (providers) who deliver acute services. This is just 59% of the 232 providers in England who deliver secondary care. The impacts of winter and the preparations to manage them require a whole sector approach across the full spectrum of acute, ambulance, mental health, community and specialist services; so while the winter sitrep data is important it needs to be placed in context. It is also a selected set of indicators so we need to consider it alongside other data sources, for example A&E data, to fully understand the impact of winter pressures.

The impacts of winter and the preparations to manage them require a whole sector approach across the full spectrum of acute, ambulance, mental health, community and specialist services

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Added to this it is notable that there are fewer trusts reporting this year. In 2016/17 there were 152 reporting trusts, however this year that has reduced to 137. Over the past year there have been three trust mergers, bringing the total down to 149; the remaining 12 are specialist providers who are no longer reporting. We therefore need to be careful when comparing this years’ data to last as the cohort is different.

This year the planned reporting period is one of the shortest. The length of the winter reporting has varied between 146 days (almost 21 weeks) to 90 days (just under 13 weeks).  Most of the focus is on what we would describe as the ‘peak’ winter months, beginning of December to end of February, and these are covered in all years.

Matching up time periods across different years is challenging, particularly because weekends and bank holidays have an impact. When comparing data across years we can either compare day to day (1^st December to 1^st December) or week to week (week 1 to week 1), however both have drawbacks. Different days of the week have different pressures, so comparing a Monday in 2016 to a Tuesday in 2017 might be showing the wrong kind of difference, i.e. the difference between a Monday and a Tuesday and not the difference between years. Comparing week to week should balance this out (every week has a Monday to a Sunday) but bank holidays produce even more noticeable variation, so if Christmas Day falls in week 5 one year but week 6 the next this will also have a significant impact.

The winter sitreps provide transparency over the emerging picture at the most challenging time of the year for the NHS.

   

And all of that is before we even get to the numbers! Over the past 6 years 16 different datasets have been reported on but only seven have been included every year. This year the sitreps report on nine key datasets (see table below). Seven of these are consistent with reporting in previous years’, one is similar to data reported previously but not for the past two years, and one is brand new.

You might be thinking that all of this is an argument for treating each year of sitrep data completely independently and that comparisons are impossible. But the key for me with this data, as with any, is that the true value comes once we understand this context and can make informed comparisons.

While the sitreps may have a very specific lens they are a unique opportunity for us to see the ‘live’ impact of external factors on our health service. As we see the snow falling one week we see the increase in ambulance arrivals when the data is released the next, without the time-lag we normally have which makes these connections become a little bit hazy as the world moves on. Perhaps this ‘live-ness’, which lifts the numbers and places them closer to reality, is why the sitreps are so significant.

While the sitreps may have a very specific lens they are a unique opportunity for us to see the ‘live’ impact of external factors on our health service.

   

 The winter sitreps provide transparency over the emerging picture at the most challenging time of the year for the NHS, as well as giving NHS England and NHS Improvement the necessary data to monitor the situation locally, and to feed in to things like the National Emergency Pressures Panel to make decisions about how the sector can best respond to these challenges. In practice it represents a small drop in the ocean of a complex picture of what is happening in a trust, a part of the country or nationally.