Housing Need and Demand Assessment (HNDA) Tool Instructions (2026)

2. Setting Up The Tool

Finding and Opening the Tool

The HNDA Tool (v5.0) is accessed from the CHMA’s website. On this page:

• click the `HNDA Tool’ link.
• click on the ‘open’ link or ‘open in new window’ to start the Tool. It takes a few moments.

Starting the Tool

The Tool contains Macros which perform calculations. If prompted:

• click ‘enable Macros’ or ‘enable contents. This activates the Macros.
• the Tool allows users to enter various data and scenarios. This should only be done at those places indicated. Changes made elsewhere in the spreadsheet can break Macros and, in turn, break the Tool.

The Tool homepage will now appear. To start working:

• click ‘Go to map worksheet.’ This brings up the ‘Area selection screen’ which shows a map of Scotland and a drop-down menu.

The drop-down menu includes every local authority in Scotland, four City Regions, and the National Parks.

• select the area of Scotland that the user wishes to work with. Note, selection of an area automatically includes any sub-areas that were provided by authorities.
• select the starting year. The default year is 2026. If users want a later year type this in.
• click ‘Set Areas’ and wait. After a few seconds, a Microsoft window will appear advising that the ‘HNDA Tool is now set up.’ Click ‘ok.’

What can Now be Seen on Screen

Different Coloured Worksheet Tabs

The light green-tabbed worksheets indicate where the user can change scenarios, input local data or input local scenarios. The ‘scenario all’ sheet is for the whole area and the `S1, S2, etc.’ sheets are for each sub-area.

The red-tabbed worksheets show the results for all areas. There are three results sheets, a summary, detailed results for the core (default) settings and detailed results for the scenarios run. The last two inform the first. More on this further on.

The purple-tabbed worksheets contain the data that are pre-programmed into the Tool and which power the Tool calculations.

Buttons at the Top of the Screen

There are two buttons at the top right of the screen:

• by clicking ‘Show Results’ a graph of the housing estimates is displayed (both the core and user scenarios) and users can see how these change as different scenarios are chosen at each stage of the Tool
• by clicking the ‘Hide Results’ button these results graphs get hidden.
• the green graph shows results based on the core (default) setting pre-programmed into the Tool. The orange graph shows the user’s results based on the scenarios/ choices they have made in the Tool.

Core (default) and user scenarios

As users choose scenarios at each stage of the Tool, those scenarios are charted. Each chart shows two sets of trends:

Green data lines represent the core (default) scenarios pre-programmed into the Tool. These do not change. Orange data lines show the scenarios selected by the user. These change as the user makes changes.

If the core and user scenarios are the same, the data lines appear on top of each other. This is how the Tool appears when opened. When the user chooses different scenarios these data lines diverge. Details of all the scenario core (default) settings are set out further on.

Graph Features

By placing the cursor over the data line it will display the value of that data point.

By clicking on the data line, right clicking the mouse and choosing `source data’ this will take the user to the data which are generating this chart. Take care not to change the source data as this could break the Tool. The source data is located beneath the charts (scroll down quite a bit to find the underlying data).

Some of the chart axes have very big scales because the numbers being charted ba different scenario is selected. However, if the user hovers the cursor over the graph they will be able to see the value of a data point changing.

Users are Nearly Ready to Start Running Scenarios

Section 3 provides a step-by-step guide to choosing and running different demographic and economic scenarios. It is important to note that there are two options when doing this:

1) choose scenarios and apply them to all sub-areas areas, in which case users will only be working on the ‘Scenario All’ sheet.

Or

2) users can vary scenarios for one or more of the sub-areas, for example where affordability differs across a local authority. In which case users will be working with not only the ‘Scenario All’ sheet but the individual sheets i.e. `S1, S2 etc.’

In this instance, first choose the scenarios for the whole area using the ‘Scenario All’ sheet. Then go to the sub-area(s) in question and alter the scenario for that area(s).

The next section is a step-by-step guide to running the Tool