What is the difference between a Filter and a Parameter?

When creating a new list, you'll notice that you have the option of adding a filter or parameter. 

Filters

Let’s start with Filters. Think of the light gray box as your first bucket. Reach will pull every patient in your EMR that matches all of the criteria in that bucket.

So if you wanted all patients less than 40 years old, whose primary diagnosis has a body part of knee pain, and who go to your Boston clinic, it would look like this:

Let's break it down. Filters use AND logic. The filters tell Reach to find patients who are older than 30 AND who have a knee injury AND who go to your Boston clinic.

You will have a very small patient population that can meet all of the above criteria, so this list is pretty exclusive.

Parameters

Using parameters is like adding more buckets. Reach will pull every patient in your EMR that matches all of the criteria of those additional buckets and add those patients to your list. So what happens if you set this list up with the same details but including them as separate parameters?

Parameters use OR logic. The parameters here tell Reach to find every patient who is either less than 40 (at any clinic or with any diagnosis), OR has a primary diagnosis = knee (at any clinic, any age), OR goes to your Boston Clinic (any age or diagnosis).

This list will be a lot larger than the previous list because the patient only has to meet one of these criteria to be included, meaning that this list is pretty inclusive.