I've used mother's maiden name (abbreviated if too long or padded if too
short)+ birthdate of mother or respondent.
Donald Burrill wrote:
>
> On 3 Aug 2000, DavidS9307 wrote:
>
> > I would like to collect data in a school on a survey form where the
> > respondents enter only a code number to identify themselves. I would
> > like the code number to be something that the participants will be able
> > to remember for follow-up data collection in the near future, but I
> > would also like to protect against identifying the participant even if
> > the forms and coding scheme were disclosed, so I don't want to use
> > birthdates, names of relatives, or SSNs.
>
> Surely you also want the codes to be unique, so that your follow-up
> analyses do not confuse Maxine with Raymond simply because they happened
> to produce the same code.
>
> > I had been thinking of using some number not generally known to anyone
> > other than the participant, such as the last digit of their locker
> > number at the school,
> "Last digit"? You ARE planning to have a sample
> size larger than ten, aren't you?
>
> > to disguise a universal identifier by adding it to each of the last
> > four digits of the SSN, but that seems rather clumsy.
>
> I take it that "adding" refers to doing arithmetic, not to merely
> appending a common value (which would not disguise things much!).
> But there is still the question of uniqueness: can you be guaranteed
> that there are no duplicates of the last 4 digits? I doubt it.
>
> > Does anyone have a suggestion for a good coding scheme?
> > Thanks to all for any recommendations.
>
> Generate a set of, say, 3- or 4-digit numbers. Print each on one side
> of a card. Shuffle the cards. Take the cards (or a sufficiently large
> subset of them) into the classroom where you introduce the survey to the
> participants. Visibly shuffle them again, and deal them (face down), or
> have assistants deal them, one to a customer. Explain why you need the
> numbers, ask them to memorize their own code (and/or squirrel the card
> away in a safe place where they can find it later), and write it in the
> space provided for the purpose on the survey response forms.
>
> If you are dealing with classroom-sized groups of participants (i.e.,
> fewer than 52 persons per subgroup) you could use ordinary playing cards
> plus a precoded identifier for the subgroup. Makes a 2-character
> identifier, possibly easier to remember than an arbitrary 3- or 4-digit
> number (though people seem to do all right with PINs for their ATM
> cards): AH for ace of hearts, 3S for trey of spades, etc. And you'd
> have to ask them to remember the subgroup identifier as well, but perhaps
> you could use a single alphabetic character for that (or a number if
> there are ten or fewer groups).
> (Make sure you remove the jokers etc. before you shuffle & deal!)
>
> ------------------------------------------------------------------------
> Donald F. Burrill [EMAIL PROTECTED]
> 348 Hyde Hall, Plymouth State College, [EMAIL PROTECTED]
> MSC #29, Plymouth, NH 03264 603-535-2597
> 184 Nashua Road, Bedford, NH 03110 603-471-7128
>
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