Millisecond Forums

Communicating a mistake: Yes. Adjust the /branch to some page or trial displaying a suitable error message. From there then /branch to the ranking page again.Storing (or rather "restoring") previous answers: No.

That's not a good news :/ Maybe there is a solution to "stop" script if two equal ranks are given? Like when you don't answer obligatory question?

What's the point then in trying to validate responses at all? But alas, feel free to define a suitable /stop attribute.

Basically we are interested in the proportion of categories of the chosen sentences (there are two categories).
I think I didn't explain it well. My point is to prepare a solution which will prevent participant from assigning ranks again when he make a mistake. Now if all conditions aren't met (the rank is doubled) the script goes back to the beginning of ranking task (erases all assigned ranks). My goal is to change it - the best would be if we can make script which simply won't go forward (and backward) - just like in case when one (or more) answer is missing; in the basic setup in that situation the missing question is marked red and "next" button doesn't react, could we do that - mark "doubled" ranks and wait for corrections without erasing all assigned ranks?

Thanks for the useful clarification. I'm afraid, though, that isn't really possible. The only thing you *could* do, is run the <surveypage> via a <survey> element (instead of a <block>):<values>
/ rankstring = ""
/ validranking = false
</values>

<survey mysurvey>
/ pages = [1=mypage]
/ showbackbutton = false
/ showpagenumbers = false
</survey>

<text debug>
/ items = ("<%values.rankstring%>")
/ position = (50%, 5%)
</text>

<surveypage mypage>
/ stimulusframes = [1=debug]
/ questions = [1=r01; 2=r02]
/ ontrialbegin = [values.rankstring=""]
/ ontrialend = [values.rankstring=concat(concat(values.rankstring,dropdown.r01.response),dropdown.r02.response)]
/ ontrialend = [if (
    length(values.rankstring) == 2 &&
    length(replaceall(values.rankstring, dropdown.r01.response, "")) == 1 &&
    length(replaceall(values.rankstring, dropdown.r02.response, "")) == 1
    ) values.validranking = true else values.validranking = false]
/ branch = [if ( values.validranking == false) surveypage.mypage]
</surveypage>

<dropdown r01>
/ caption = "Rank 1"
/ options = ("Object A", "Object B", "Object C", "Object D")
/ optionvalues = ("A", "B", "C", "D")
/ required = true
</dropdown>

<dropdown r02>
/ caption = "Rank 2"
/ options = ("Object A", "Object B", "Object C", "Object D")
/ optionvalues = ("A", "B", "C", "D")
/ required = true
</dropdown>That will preserve previous responses, but it has other drawbacks: (1) The results will end up in a separate, differently formatted data file and (2) you will not get any record of how many times a given person had to adjust the ranking until he/she got it right.

That's perfect solution for me. Thank you.