CoderDojoDC/signin — pull request #1 by jhandley (2014-08-24 12:39:50+00:00)
Title: Multi-select field for interests

Multiple response variables in CSPro are usually implemented as alpha values where each response is represented by a different letter. So in your value set you have:

Arduino	A
Scratch	B
HTML	C
Python	D
Minecraft	E
Raspberry Pi	F

So if the user picks Arduino, Scratch and Python then the response would be: "ABD". The variable has to be the same length as the value set in case someone picks every option. Once you set up the dictionary variable this way then on the field properties you can pick "check box".

See http://www.csprousers.org/help/html/extended_controls.htm

There is some history to this method. If you think about keying in data from a paper form, this approach uses a lot less keystrokes on average than typing y/n or 1/0 for each option. When you are keying millions of forms every keystroke counts.