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Dispensing days includes week days and Saturdays but excludes Sundays and Bank Holidays.
Other Forecasting Methods
As a result of feedback from stakeholders and our work in developing the PCT Prescribing Report, we have had several enquiries as to whether we could assist PCTs with forecasting prescribing expenditure. Consequently, we have carried out research into different methods that PCTs could use to forecast expenditure on drugs. The results of this research showed that two forecasting methods could be useful to PCTs in addition to the forecast outturn calculation included in the PCT Prescribing Report and ePACT.net. A spreadsheet has been developed for you to calculate your forecast expenditure for the year and you can download this from the links below.
Forecasting Spreadsheet 2008-2009
The two forecasting methods used in the spreadsheet are the linear trend method and the moving averages method. The linear trend method is the simplest of the two and is calculated by drawing a best fit line through previous data and extrapolating this line into the future. The moving averages method smoothes the data in such a way that the effect of random variation is reduced and the underlying pattern is easier to see.
The advantage of the linear trend method is that it is simple to calculate and understand however, it can be easily skewed by extremes in expenditure (e.g. expenditure is often high around October due to prescribing of influenza vaccines. This peak skews the data and artificially high forecasts are produced.)
The advantage of the moving averages method is that the smoothing process produces more stable forecasts from month to month. The drawback to this method is that it reacts slower than other methods to permanent changes to the level of expenditure, for example policies such as the Pharmaceutical Price Regulation Scheme and the Generic Prices Review could mean that forecasts based on old higher prices will be too high. In this case, additional calculations could be carried out locally to estimate the impact of such policies and the forecast adjusted accordingly.
Local prescribing policies could also affect the forecasts and such policies need to be taken into consideration when estimating expenditure.
We would welcome your comments or suggestions about the information and forecasting methods contained on this page.
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