Re: "Anonymous" survey with user matching

Session is cleared after a successful submit, so storing something there 
is not useful.

Basically, you can't be sure the user answers from the same computer, so 
nothing you store client side (cookies etc) can be trusted either. You'll 
have to give the user a ticket to carry on manually to the next survey. If 
you're strict about authentication, none of the authentication schemes 
will work either.

I'd suggest autogenerating a string somehow, print it as the default value 
in a text box on first page and ask the user to write it down and enter it 
manually in the next survey.

<SURVEY TITLE="code">

   <CUSTOM ESCAPED="no">
     The number in the textbox below is your unique generated identifier. <br /><br />
     <b><u>IMPORTANT!</u></b> write it down, you will need it in the followup. <br /><br />
     (Note that if you forget this number, there is no way to recover it, it is simply
     the time you accessed the survey plus a random number)<br /><br />
     If you think this value is too tricky to remember, you can enter anything else you want in the text box, but please pick something you think no-one else will pick.
   </CUSTOM>

   <TEXT NAME="userkey" CAPTION="Unique key" DEFAULT="{&

     $key = $session->{SESSION_ID};
     ($part1,$crap) = split(/\./,$key);
     $part1 =~ s/\_//g;
     $key = $part1;
     print $key; &}" />

</SURVEY>

The suggested string here is rather long, maybe you can figure out a 
better approach. It is the session id minus the IP number of the 
respondent and with underscores removed.

   // Joel


On Fri, 23 Nov 2007, Ross Richardson wrote:

>
> A group here is interested in conducting two surveys (initial and
> followup) and, whilst they wish the respondents to remain anonymous,
> they wish to be able to match respondents between the surveys.
>
> Has anyone advice on how this might be achieved?
>
>
> I'm thinking of requiring authentication, then including in the results
> data some non-identifying value derived from the username - for example,
> an MD5 hash of the concatenation of some secret string and the username.
>
> In terms of practical implementation, I've only just started
> experimenting with perl snippets and have run into the problem that
> others have noted: the following doesn't work...
>
> 	<SUBMIT>
> 	{|
> 		$session->setValue("user_id", "some_value");
> 	|}
> 	</SUBMIT>
>
> Assistance would be greatly appreciated!
>
> rlr
> -- 
> Ross L Richardson               <URL:mailto:[email protected]>
> Senior Systems Administrator                  Phone : +61 (0)3 6226 6233
> Information Technology Resources                Fax : +61 (0)3 6226 7171
> University of Tasmania, AUSTRALIA
> Skickat av Ross Richardson <[email protected]>
> till survey-discussion
>
Skickat av Joel Palmius <[email protected]>
till survey-discussion