# Limits to EObs

**URL:** <https://forum.certara.com/t/limits-to-eobs/3700>\
**Category:** Modelling and Simulation\
**Created:** [September 6, 2023, 9:15am UTC](https://forum.certara.com/t/limits-to-eobs/3700 "2023-09-06T09:15:05Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![frrd](https://avatars.discourse-cdn.com/v4/letter/f/3e96dc/32.png) [@frrd](https://forum.certara.com/u/frrd)\
**Post date:** [September 6, 2023, 9:15am UTC](https://forum.certara.com/t/limits-to-eobs/3700/1 "2023-09-06T09:15:05Z")

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I have some activity data from mice in time bins. The observed data is in percent of time they are mooving. If the mice are stimulated many will move around 100% of the time. However, some of the mice that moove 100% of the time are more stimulated than others so we observe a ceiling effect. So the real Emax is higher than the observed Emax which is limited by a ceiling of the measurements. I would like to convert my PD model with a ceiling effect so that. eg (0,0.3,0.9,1.2,1.5) preddicted from the model is converted to (0.30,90,100,100). I tried

logit(Emax\*E/EC50+E)

or

E= ln (EB / (1 - EB))

EB= Emax\*E/EC50+E

However both ln and logit does not work in the model structure. Is there another way to do this effect prediction with a ceiling?

BR Frederik

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**Author:** ![Samer\_Mouksassi](https://avatars.discourse-cdn.com/v4/letter/s/ce7236/32.png) [@Samer\_Mouksassi](https://forum.certara.com/u/Samer_Mouksassi)\
**Post date:** [September 6, 2023, 9:30am UTC](https://forum.certara.com/t/limits-to-eobs/3700/2 "2023-09-06T09:30:22Z")

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HI Frederik,

you might need a trauncated model where you have an upper limit of quantification here Emax

you will need to write your LL statment as we do not have this built in.

Bests,

Samer

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**Author:** ![frrd](https://avatars.discourse-cdn.com/v4/letter/f/3e96dc/32.png) [@frrd](https://forum.certara.com/u/frrd)\
**Post date:** [September 6, 2023, 9:57am UTC](https://forum.certara.com/t/limits-to-eobs/3700/3 "2023-09-06T09:57:07Z")

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ok. I will look into how to write my own LL statement.

Thx Frederik

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<div class="post-metadata">

**Author:** ![Samer\_Mouksassi](https://avatars.discourse-cdn.com/v4/letter/s/ce7236/32.png) [@Samer\_Mouksassi](https://forum.certara.com/u/Samer_Mouksassi)\
**Post date:** [September 6, 2023, 10:12am UTC](https://forum.certara.com/t/limits-to-eobs/3700/4 "2023-09-06T10:12:57Z")

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also look at : [https://support.certara.com/forums/topic/1189-how-to-deal-with-values-above-the-upper-limit-of-quantification/?hl=%2Bupper+%2Blimit](https://support.certara.com/forums/topic/1189-how-to-deal-with-values-above-the-upper-limit-of-quantification/?hl=%2Bupper+%2Blimit)