# 📓 Understanding the algorithm

**Explanation of the Algorithm's Logic:**

**Initial Probability**: Begins at 100% for initial weight as it is shared by the partner via API

**Variables taken into account for calculation:**The algorithm takes in consideration both the time duration between measurements and the weight difference between measurements to return the probability value.**Weight and Time Delta Calculation**: It calculates the difference in weight and time from the last recorded measurement and increase or decrease**Probability Adjustment**: The probability is then adjusted based on these deltas. Smaller changes within a short period increase the probability, while larger changes decrease it, unless overridden by user feedback.**User Feedback Function**: An API to confirm/reject a measurement is available to improve probability accuracy for future measurements. The probability of the current will be adjusted to either 0% or 100% based on user feedback, overriding the calculated probability.

### When to ask for user confirmation ?

- If the probability score returned by the getmeas API
**is below 70 and above 50**, Withings recommends sending a push notification or SMS to the member to request confirmation or rejection of the weight. - If the probability score returned by the getmeas API is
**above 70**, the weight likely belongs to the end user. However, to enhance accuracy, Withings still advises providing an option for confirmation or rejection in your member or coach app for optimal results. - If the probability score is below 50, program member id is fairly confident the end user is not your program member. However, it is still recommended to provide a confirmation from time to time or if you think a confirmation mistake has been made.