# Adding Adoptive Staircase

**URL:** <https://discourse.psychopy.org/t/adding-adoptive-staircase/9358>\
**Category:** Builder\
**Created:** [October 10, 2019, 2:54pm UTC](https://discourse.psychopy.org/t/adding-adoptive-staircase/9358 "2019-10-10T14:54:01Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Abdul](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.psychopy.org/abdul/32/5855_2.png) [@Abdul](https://discourse.psychopy.org/u/Abdul)\
**Post date:** [October 10, 2019, 2:54pm UTC](https://discourse.psychopy.org/t/adding-adoptive-staircase/9358/1 "2019-10-10T14:54:01Z")

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If this template helps then use it. If not then just delete and start from scratch.

**OS** : Win10  
\*\*PsychoPy version: (3.2.4)  
\*\*Standard Standalone? (yes)  
\*\*What are you trying to achieve?:  
Hi,

I’m trying to create an acuity test in which a square stimulus is fixed at the center of the screen x and y = 0; (0, 0) and another similar stimulus would be presented 3 units above the fix stimuli but ranging from (-0.5 to 0.5) positions example (-0.5, 3) to (0.5, 3) in 0.1 unit difference, where the presented stimuli is asked to mark left or the right-hand side using left and right arrow keys respectively and ‘space’ key if vertically aligned with the fixed stimuli at position (0, 3).

I would like to apply an adaptive staircase to it and check the number of correct responses for a vertically aligned position.

**What did you try to make it work?:**  
In this direction, I’ve created a trail loop and opted for random mode with conditions to be loaded from excel. However, when I tried switching to staircase it is challenging for me to understand and add certain pieces of code.

Here are my experiment file and a condition file for your reference.

[Interleaved condition.xlsx](https://discourse.psychopy.org/uploads/short-url/bHlMlV4OQxZns0ZFVEsOMXPf7Rs.xlsx) (9.9 KB) [Interleaved\_working\_1008.psyexp](https://discourse.psychopy.org/uploads/short-url/cwQmiVW3YJtLcdw36CqxOdMLK7J.psyexp) (15.9 KB)

It would be great if anyone can help me with fixing this issue.

I want it to be in a step size of ((0.2,3), (0.2,3), (0.1,3), (0.1,3)) based on the correct/incorrect response it should decide the position close or far from the vertical alignment position in a staircase model.

Many thanks in advance.  
**What specifically went wrong when you tried that?:**  
Include pasted full error message if possible. “That didn’t work” is not enough information.

 ![Error](https://us1.discourse-cdn.com/flex002/uploads/psychopy/original/3X/d/5/d58750ff7f7b8341ffdea126a973c0afa54bd4a0.jpeg)

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<div class="post-metadata">

**Author:** ![jon](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.psychopy.org/jon/32/22_2.png) [@jon](https://discourse.psychopy.org/u/jon)\
**Post date:** [November 11, 2019, 10:34am UTC](https://discourse.psychopy.org/t/adding-adoptive-staircase/9358/2 "2019-11-11T10:34:21Z")

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I think the issue might be that you’re trying to specify 2 stpe sizes for each step size - PsychoPy staircases use a single step size for steps in both directions. To home in on a typical threshold (79%) you would use the same step in each direction but a 1-up/3-down approach