---
title: "Calculate field codes in background"
url: "https://openforis.support/questions/3321/calculate-field-codes-in-background"
tags: ["openforis", "collectmobile"]
status: "answered"
score: 0
answer_count: 1
asked: "2022-02-03T11:23:49"
last_activity: "2022-02-03T12:02:52"
source: "Open Foris Support - Q&A Forum"
license: "Copyright Open Foris, 2026. Some rights reserved under creative commons license."
---

# Calculate field codes in background

Asked by janklein on 2022-02-03

Hi,

I would like to know if and how it is possible to create fields that are automatically calculated in the backgound for each observation but which will not appear in the collect mobile survey.

In my concrete case, I require three distinct field codes for each individual but in the collect mobile survey, I would like to have displayed only a single one of these while the other two should be calculated in the background. For the export, I require all three of them.

Thanks a lot in advance,
Jan


## Answer (score 0, by Stefano (OF) on 2022-02-03)

Link: https://openforis.support/questions/3321/calculate-field-codes-in-background/3322

Dear Jan,  
In the survey designer you can mark an attribute as "Calculated", uncheck the option "Show in entry form" and then specify how to calculate the value in the "Calculated Value Expressions" section, similarly as when you define a default value for an attribute.  
![alt text][1]
![alt text][2]  

If you look at the Collect user manual, you will find some examples of the most common expressions to use.  
Many thanks,  
Open Foris Team


  [1]: https://openforis.support/upfiles/Screenshot_2022-02-03_12-00-53.png
  [2]: https://openforis.support/upfiles/Screenshot_2022-02-03_12-00-13.png