# Penetration mapping with Z-scores Based on the capabilities of the Profile tool, penetration mapping provides valuable insight by allowing you to compare two groups of people on a map using an analysis to base index statistic. However, the results for all areas are not necessarily statistically significant. When creating a profile, this is overcome by each category having a Z-score statistic assigned to it, but only those that are significant add a score to the model. From the Q2 2025 software release, this approach can be applied to a penetration map and used to control whether or not an area is shaded. There is also a further option to shade and identify significant areas on a map using the Z-score itself. ## Example 1 ### Only apply index shading when the Z-score of a particular area exceeds a statistically significant threshold (default ± 3.0). Areas which are not statistically significant should not be shown To get started: 1. Open a new **Map**. 2. In the **Layer 1** tab, add **Postal Area** as the geographic variable to use. 3. Click **Selections** on the map toolbar. The **Map Selections** dialogue opens with two tabs. 4. Within the **Analysis Selection** tab, drag and drop a selection of **Sweden Holidaymakers** into the **From Selection** drop-box. 5. Switch to the **Base Selection** tab where you can see that the default is **People** - i.e. all people on the database. Leave as the default. 6. At the bottom of the dialogue you can select the calculated insight metric - in this case choose **Analysis Base Index** and **OK**. 7. **Build** the map. You can see that thematics have been applied and hovering over a shaded postal area displays the corresponding index value. Here, the index values indicate that the areas around London, Birmingham and Manchester have a higher penetration and mid-Wales lower, suggesting that Sweden holidaymakers are generally located in more urban areas, although there are clearly some outliers, such as the Isle of Man, Glasgow and Hull. ### Applying thematic shading based on index values To provide further insight you can choose to apply thematic shading specifically for the index measure: 1. In the **Layers** panel, select **Thematic** to access the **Edit layer thematic** dialogue. 2. From the **Type** drop-down, select **Index shading** and set the number of ranges to **5**. 3. Select appropriate thematic colours - in this example, shades of blue for values below 100 and shades of red above. 4. Click **OK** to update the map display. The insight? You can clearly see the under and over representation of Sweden Holidaymakers v All People by Postal Area. Whilst representation in most areas appears to be about average, the Isle of Man is strongly over-represented and there are several areas - from Plymouth in the south west, to Llandrindod Wells in Wales and Kirkwall in Scotland which are quite significantly under-represented. ### But are all these areas statistically significant? To further investigate: 1. Click back on the **Selections** icon. 2. In the **Measure To Display** panel, check **ZScore threshold** and **OK**. The default is ± 3.0, but you can adjust this if you wish. 3. **Build** the map. The map now only displays shading for postal areas where the results are statistically significant. ## Example 2 ### Create a map that displays actual Z-scores 1. Click on the **Selections** icon and select **Analysis Base ZScore** as the measure to display, then **OK**. > **Note** > > Pop-up warnings prompt you to change the thematic settings. Acknowledge these by clicking OK and then follow the steps below. 2. In the **Layers** panel, click **Thematic** and then select **ZScore shading** from the **Type** drop-down. 3. Click OK to see an updated display based on Z-score shading. The updated map clearly displays the areas which are statistically significant - and those which are not. Hover over an area to see its Z-score. > [!NOTE] > > Don't forget - you can easily convert your map into a cube, tree or word cloud using a right-drag action - see [Switch visualisations](). You can also select from the map using the legend - see [Selectable thematic map legends]() for how-to steps. Related topics: - [Penetration mapping]() - [Penetration mapping - outside population]()