# How to calculate 50% success threshold?

**URL:** <https://neurobb.com/t/how-to-calculate-50-success-threshold/1148>\
**Category:** Software\
**Tags:** neurofeedback\
**Created:** [September 9, 2019, 2:39pm UTC](https://neurobb.com/t/how-to-calculate-50-success-threshold/1148 "2019-09-09T14:39:36Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![khofstadter](https://neurobb.com/user_avatar/neurobb.com/khofstadter/32/250_2.png) [@khofstadter](https://neurobb.com/u/khofstadter)\
**Post date:** [September 9, 2019, 2:39pm UTC](https://neurobb.com/t/how-to-calculate-50-success-threshold/1148/1 "2019-09-09T14:39:36Z")

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In ‘Getting Started with Neurofeedback’, the author, Demos explains 50% success threshold:

> "… the threshold bar has been set so that reinforcement is received about half of the time. "

I guess I could start with using a timer that measures how long the signal is above and below threshold. Then, depending on the percentage, I could manually move the threshold up or down.

What I am not sure about is how long I need to run the timer. Do I calculate this success in a 10 second time period or longer?

Is this time period the same for all brainwaves e.g. theta and alpha?

Cheers, k