Text Analysis With Power BI Copilot

Power BI reports are usually used to display numeric data. However it is reasonably common to have text data in a semantic model too and for this to be displayed on a report, and while visuals like the new text slicer allow you apply filters to the text, large amounts of text can still be difficult for end users to make sense of. Recently I was wondering if Power BI Copilot can be used to summarise text data (similar to what is possible with Excel Copilot) and it turns out that the answer is yes – with some limitations.

To test this I created a simple semantic model consisting of a single table containing comments from diners at various restaurants:

I then created a report with (1) a slicer on the Restaurant field, (2) a table visual to display the contents of the Feedback field for the selected restaurant, and (3) a Smart Narrative visual:

For the Smart Narrative visual I used the preview Copilot option, restricted it to look at just the table visual, and used the following prompt:

Under a title, in bold, of "Feedback Summary" provide a brief summary of the comments in the Feedback column in no more than two bullet points. Include some quotes from the Feedback column but do not just repeat what is there.

And guess what, it works:

[Notice that when you change the slicer selection you have to click the Refresh button on the Smart Narrative visual to get it to update]

BUT before you get too excited, there are a few things you need to understand:

• At the time of writing the flavour of Power BI Copilot used by the Smart Narrative visual can only summarise data that is visible on the report page – if it isn’t visible, even if it is present in the semantic model, then it can’t be summarised.
• It can only consider the first 30000 rows from any given table visual, and if it is pointed at multiple visuals then it can only consider 150000 rows in total.
• For each table row, it can only consider the first 100 characters of text – anything after that will be truncated. This will be increased to 500 characters of text soon but even then this could be a big limitation (for example the text “If you want good food you have to pay. That said, it’s very good value for a Michelin-starred restaurant.” is 105 characters long). You could work around it by splitting the text up into multiple rows where the length is less than the limit, but I don’t know what impact this would have on the quality of the results.
• For most scenarios cost would not be a worry (see here for my post on the cost of Copilot; it’s the number of words, not the number of characters, that is significant), but even with the character limits if you had a lot of users trying to analyse a table displaying thousands rows of text values that is filtered/sliced regularly then it could get expensive.

As a result of this you should only consider Power BI Copilot for summarising relatively short pieces of text; you should not store long documents in your semantic model and expect Power BI Copilot to be able to summarise them. If you want to show summaries of longer pieces of text your best bet is to create them upstream before the data reaches Power BI.