4 Adjustment Factor (AutoSens)

Settings –> Preferences –> Dynamic Settings –> Adjustment Factor

Adjustment Factor is a multiplier that impacts insulin delivery. It determines the aggressiveness of the DynamicISF algorithm, and it tends to be person-specific.

Basically, it’s determining how sensitive/resistant you are compared to your baseline. An AutoSens value of 1 means that your sensitivity is what the system expects.

  • More than 1 means that you’re needing more insulin than your baseline
  • Less than 1 means you are currently more sensitive and need less insulin

The default is set at 1, which means that there is no change from those Settings values that affect insulin delivery.

A full explanation of AutoSens can found in the OpenAPS documentation.

4.1 Ballpark Formula

There is a formula for deriving an approximate number to begin with:

adjustmentFactor = 277700/TDD * BG_target * (18 * 18) * StaticISF

  • Total Daily Delivery (TDD) can be found by tapping the green circle at the top of the main FAX-ng page. There are three numbers in the purple area: TDD, Weighted Average (Wavg), and 7day. Use the TDD value.

  • BG_Target is whatever you have chosen for your target, e.g. 5.5.

  • Use the Autotune value for StaticISF

    • Settings –> Configuration –> Autotune

Autotune runs automatically every day, but you may want to run it now if it hasn’t run for a while.

  • The Autotune value also can be found in
    • Settings -> Configuration –> Insulin Sensitivities –> Autotune –> Calculated Sensitivity

Using some example numbers, the AdjustmentFactor will be:

277700 / ( 2.31 * 78.75 * 5.5 * ( 18 * 18 ) * 2.31) = 0.856

It isn’t 100% accurate, but it gets you into the ballpark range, and you can tweak up or down from there.