Using the Variable Index Preview

A variable's index determines which information from a patient's note is sent to the LLM for analysis. A variable's index can impact token usage by changing the number of tokens from the note that are sent to the LLM. This can also affect the sensitivity of a variable if the note information sent is too narrow.

The Variable Index Preview allows you to see the expected results for different indices for a variable to help you evaluate the tradeoffs for your project.

Accessing the Brim Variable Index Preview

You can access the Variable Index Preview in two ways.

From the Document View

You can get to the document view by selecting a Note or Patient and clicking "Document View" at the top of the page. Once there, find the Variable Index Preview by:

1. Selecting a specific note by finding it in the list and clicking "View".
2. Selecting the search icon on the top right of the document panel.
3. Selecting "Preview Variable Index"
4. Choosing a variable to preview.

From the Edit Variable Page

You can access Variable Index Preview in the Advanced Variable Settings. To find it:

1. Go to Project Setup > Variables and click "Edit" for the variable you wish to preview.
2. Scroll to the bottom of the screen and access the Advanced Settings by clicking "Show Advanced Settings"
3. Scroll to the "Index Type" setting.
4. Clicking "Preview Index for a note", which will open a new tab allowing you to preview your index on a patient note.

Using the Variable Index Preview

The Variable Index Preview is a powerful tool for understanding which index is likely to be the best choice for a given variable and application.

• Basic Settings. The top of the screen allows to to choose the variable and index you'd like to preview. The index options are Standard and Prefiltering.
• Configure Menu. If you click the "Configure" button, you'll be given a menu of options to customize the index.
  • Prefiltering: Surrounding Lines. This determines the number of lines around a search term that are included.
  • Prefiltering: Terms to Always Include. This is a list of search terms to always include when looking for relevant text for this variable.
  • Prefiltering: Terms to Always Exclude. This is a list of terms to always exclude when looking for relevant text for this variable.
  • Save index and settings. This allows you to save changes to your variable index and settings directly to your variable.
  • View variable link. This opens edit variable in a separate tab.
• Tokens sent comparison graphs. This view helps you understand token savings for this note and patient. It will show how many tokens would be sent to the LLM for this note and patient for Standard Index, Prefiltering index, and then the estimated percentage change.
• Search terms. This shows the list of search terms driving the text highlighting in the note.
• Note highlighting. You'll see the parts of the note that are sent to the LLM because they are considered relevant to a search term highlighted in green in the note below.
  • Prefiltering sends lines containing a search term, as well as the number of surrounding lines specified in the index settings. The matching lines will be shown in green, and the surrounding lines in yellow.