Calculations

Adjustments for GDP (Gross Domestic Product)

Where possible, historical spend data is adjusted for inflation using GDP deflator factors to compare spend over time in real terms. Figures have been fixed at 2017/18 prices. Using GDP deflators removes the affect of changes in price (inflation) from a time series so for example, the 2013/14 spend per head represents what that figure is worth in 2016/17 prices. More information on the GDP deflator series is on the Treasury website. The GDP adjustment is made by multiplying the value of the indicator by the corresponding value for each period listed in the table below:

Year2017/182016/172015/162014/152013/142012/132011/122010/112009/102008/092007/08
Value1.00001.01901.04161.04991.06341.08291.10471.11921.14001.15621.1876

The planned budget section uses data from a different time period to the rest of the profiles. Data in this section are fixed at 2017/18 prices where 2017/18 data are multiplied by 1.000 and 2016/17 are multiplied by 1.0152, etc.

Year2018/192017/182016/172015/162014/152013/142012/132011/122010/112009/102008/092007/08
Value1.00001.01521.03251.05561.06401.07771.09781.11951.13431.15541.17171.2035

Adjustments made to planned budget data

We have used the RA form as our starting point. We have adjusted planned budget to allow for a more accurate comparison of service expenditure and funding between years to remove services that are outside of the council’s control - such as education and police services.

Standardisation for population

Often expenditure data have been divided by population denominators to show, for example, spending per head, per 1,000 people, or per young person. The numerators and denominators used to produce the calculations can be found in detail indicator report or by clicking on the indicator value.

Polarity

  • Indicators are assigned a high polarity if a higher data value is better than a lower one (for example employment rates).
  • Indicators are assigned a low polarity if a lower data value is better than a higher one (for example unemployment rates).
  • Contextual indicators (for example population size) and expenditure indicators are assigned no polarity.

Direction of travel (DoT)

This calculation compares the value for the latest period with the previous period and uses polarity for selected indicators.

  • Improving - A green arrow that points shows an increase in performance. This could apply for indicators that have high or low polarity. For example, if polarity is high and the value for the latest year is higher than the previous year the arrow will point up. Alternatively, if an indicator's polarity is low and the value for the latest year is lower than the previous year the arrow will point down.
  • No change - An orange double-sided arrow will appear for indicators that have either high or low polarity. This symbol shows there is no change as the value for the latest year is the same as the value for the previous year.
  • Worsening - A red arrow pointing shows a decrease in performance. This might apply for indicators that have high or low polarity.  For example, if polarity is high and the value for the latest year is lower than the previous year the arrow will point up. Alternatively, if an indicator’s polarity is low and the value for the latest year is higher than the previous year the arrow will point down.

Indicators that have no polarity will show a direction of travel with blue arrows, these do not associate an increase or decrease of a value with performance:

  • Increasing - A grey arrow pointing up shows the value of the indicator has increased since the previous year.                                                 
  • No change - Where the value remains the same as the previous year an orange double-headed arrow will display.
  • Decreasing - If the value of the indicator is lower than the previous year, a grey arrow pointing down will display.

Averages

Where the average is used it is the arithmetic mean, and is calculated by adding a group of numbers and then dividing by the count of those numbers. For example, the average of 2, 3, 3, 5, 7, and 10 is 30 divided by 6, which is 5.

Calculating outliers

If a data value is more than 2 standard deviations above or below the mean of the comparator group you have selected it will appear in the outliers report. If there are no outliers for the authority this report will be blank.

Interpreting the box plot

A box-plot provides a visual presentation of the quartiles of the data.

 

The box in the middle of the box plot shows the middle two quartiles of the comparator group you have selected. Half of all the organisations in comparator group fall within these two quartiles. The lines in the middle of the box show the mean and median values of the comparator group.

 

Coming out of the top and bottom of the box are two fences (or whiskers as they are also known). The fences show the range of the upper quartile on the top and the bottom quartile on the bottom.

 

The size of the range of each quartile varies, but the number of cases in each quartile remains the same.

 

The shape of the box plot provides some clues about how the data are distributed. For example if the box plot is squashed it shows the range of the data is small. If the box plot shape is uneven it suggests that the data distribution is skewed.

Text that appears when data values cannot be shown

The table below describes values that may appear in the data tables other than the actual data and their meaning:

  • Unable to calculate - These words appear in the table when there are not enough values for the performance indicator to create a calculated result. This will occur if one or more values expected to be available for a calculation do not exist or there are issues with the quality of the data. For example, the result for direction of travel is available when a value exists for the latest year and the previous year. If one of the values for the indicator is missing, the table will display the words not calculated.
  • This indicator is not applicable to this authority - This appears when there is no value for the selected organisation. This could occur for two reasons, either the data values for the indicator are not available publicly or the value for the selected authority is not available in the dataset.
  • The value is missing - This appears where we expect a value for the indicator to be available but it does not exist.
  • The value is suppressed - When the word ‘suppressed' appears it shows the data is withheld from publication. When suppressing a value for a performance indicator we will exclude the result from calculations.