Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!bellcore!usenet
From: nielsen@bellcore.com (Jakob Nielsen)
Newsgroups: comp.cog-eng
Subject: Studies with more than 40 test users
Summary: Request for data from large-scale empirical HCI studies
Keywords: Subjects, power tests, statistics
Message-ID: <1991Jan15.222612.8008@bellcore.bellcore.com>
Date: 15 Jan 91 22:26:12 GMT
Sender: usenet@bellcore.bellcore.com (Poster of News)
Organization: Bellcore - Bell Communications Research
Lines: 20

Most empirical studies and user testing seems to be done with a rather small
number of test users. Indeed, I often recommend the use of small samples
myself for practical usability engineering purposes.
For some current research on the statistical characteristics of user testing
and the effect of varying the number of test users, I need access to larger
data sets with results from empirical tests of user interfaces.
Let us say that "large" = 40 subjects in the HCI field, even though this
is modest compared with other fields where one can easily find studies
with thousands of test users.
I am interested in both objective measurements (such as time or errors
when completing some task) and/or subjective measurements (user preferences
or heuristic evaluations).

If you have such data sets and might be willing to let me look at them,
I would be grateful for an email message. It does not really matter
what systems you studied, and I can let you remain anonymous or give
you credit as you like. 
--
Jakob Nielsen, Bellcore MRE-2P370, 445 South St, Morristown, NJ 07962-1910, USA
email nielsen@bellcore.com, tel. +1-201-829-4731, fax +1-201-538-9093