User guide to the Atlas in Healthcare Variation
The Atlas is a powerful tool which allows us to look at heath care variation in New Zealand. The Atlas is quite simple to use but we recommend you read the following guidance on creating reports first to ensure you get the best out of it.
Single map views
We have a number of different styles of Atlas page. The simplest of these is the single map display which is the main link on the Atlas pages.
The map uses colour to show differences between geographical areas. As the value of a particular indicator increases so the colouring for the area gets darker. This makes geographic patterns immediately recognisable.
In most of the Atlases the geographical areas represent District Health Boards (DHBs) however, we may use other boundaries where these are more appropriate.
Viewers can zoom in and out on the map using the map slider in the top left of the map.
The map, bar chart (bottom left) and table (top right) present the same data. All three are linked so that clicking or hovering over an area of the map also highlights the relevant bar in the bar chart and line in the table.
The bar chart shows the distribution of results from low to high and again categorises using colours in exactly the same way as the map. The Y axis to the left of the bar chart shows the range of values for the selected indicator.
It is important to recognise that although the atlas compares areas it is not a league table. This is because we do not prescribe what the “correct” level for any area should be. We cannot assume that high is good and low bad, or vice versa or even that the average is about right and the extremes wrong.
The results table shows each area and the actual value of the indicator. By clicking on the header of the table we can sort by either the area name or the value
The classification of the area is given by the coloured dot on the far left of the table – this classification is exactly the same as that used in the map and the bar chart.
Right at the top of the page is a button labelled Data. This acts as a switch that changes the Data Explorer into a pie chart and vice versa. The pie chart shows how many areas are in each category for that indicator, and it also acts as a switch for selecting all areas that belong to a particular category. If you click on a specific slice, this highlights all areas in this group on the map, the bar chart and the table.
The Data Explorer box on the left of the screen allows users to choose which indicator is displayed. When a new indicator is selected, the map, bar chart and results table all change.
Below the indicator selector is the Legend. The legend shows the meaning of the colour categorisations – with the highest values represented by the darkest colouring. In most cases we use a statistical technique called a standard deviation to set the categories and their thresholds. This measures how different an area is from the national average.
Also along the top of the screen are buttons labelled DHB comment, Methodology and User Guide.
DHB comment provides a link to any commentary provided by the DHBs about their position, such as explanations of unusual results.
Methodology provides detailed information about the indicator, where the data comes from, how the indicator is calculated and what it is measuring. This opens in a new window
User guide takes you back to this guidance.
Commentary This box provides commentary about each indicator including:
- What the measure is in high level terms (detailed definitions being available via methodology button)?
- Why the measure matters.
- Examples of questions that may be stimulated by it.
The Atlas is designed to stimulate questions. Therefore we have engaged clinical experts in these areas to help us make sure we measure what matters and place the measures in a relevant context.