tammo wrote: At that time I did not have time to dive into the possibilities of linking surveys, but now I have. I started to write an article (for the documenation) about this, which I want to share and discuss here.
Do you really see linking as a way to cope with the "unusual" database design for a survey system?
If big surveys would be top priority, we would see signs to get rid of the "unusual" database design now.
Even LS 3.0 will keep the "unusual" database design.
If linking/bridging surveys would be a top priority we would have seen some improvements in that area till today.
Linking / Bridging surveys are adding a lot of problems.
1. The survey design on paper has to be completely different.
Why? When linking surveys you cannot access all questions via conditions / EM.
You need to create proxy variables which all needs to put via GET parameters.
It is very difficult handle e.g. open text fields or arrays which needs to get converted to get transferred from one survey to another. So you have to minimize the amount of data which needs to be exchange between the survey parts. Which means changing the order of questions. Even then you end up with a lot of extra handling of variables.
2. Issues with sessions/tokens
Having more than one survey linked, bring up new issues with granted things.
E.g. when using tokens, a respondent cannot enter the survey again after finishing the first survey.
The link from the invitation is for the first survey. If the respondent gets lost in the second survey, there is no way to enter again. At least if you want to want to prevent to fill-out again the first survey.
Limesurvey is also big when it comes to session files. You end up with more space for sessions files as well.
You no longer can ensure that people can click a button to delete all given answers and leave the survey.
People are not able to go back from the second survey to the first one. You need to disable backward button at all or you end up with just one page without a backwards button.
3. Design issues
You need to tune things like progress-bar to ensure that you're not starting in the middle of the surveys at 0% again.
You need to change the submit button at the end of the first survey to next page.
Bridging surveys : Progress Bar Settings and no submit-button
bugs.limesurvey.org/view.php?id=9677
For the LTS version there is a workaround for the progress-bar tuning in that feature request ticket as well.
Your effort explaining the URL GET parameter handling will bring users to experience the bigger issues around linking surveys. Thanks for writing a more accessible manual section.
Question: Why do you want to assign external variables to equations? I see no difference to short text as a place to save things. In the past I had issues assigning values to number fields. From reading your text that seems to have changed. I no longer use LS that often, so I haven't check it by myself.
I never experienced issues with big surveys but I often needed to integrate a third party survey inside a LS survey. So I often ended up with three surveys linked together. Depending on the survey design the amount of additional work was amazing.
If you need to link surveys because one survey is too big you might need to add lot more proxy variables then I can imagine.
I have high hopes regarding the online marketing manager position.
One task is "Competition monitoring and analysis" which means that LS GmbH has to define the userbase and their demands. Which will reduce the amount of discussion around what user really need or not.
If the main competitor is SurveyMonkey, users will expect limits in this range:
help.surveymonkey.com/articles/en_US/kb/...-or-character-limits