For 11 studies, we find that the detection of usability problems as a function of number of users tested or heuristic evaluators employed is well modeled as a Poisson process. The model can be used to plan the amount of evaluation required to achieve desired levels of thoroughness or benefits. Results of early tests can provide estimates of the number of problems left to be found and the number of additional evaluations needed to find a given fraction. With quantitative evaluation costs and detection values, the model can estimate the numbers of evaluations at which optimal cost/benefit ratios are obtained and at which marginal utility vanishes. For a “medium” example, we estimate that 16 evaluations would be worth their cost, with maximum benefit/cost ratio at four.
Description
A mathematical model of the finding of usability problems
%0 Conference Paper
%1 169166
%A Nielsen, Jakob
%A Landauer, Thomas K.
%B CHI '93: Proceedings of the INTERACT '93 and CHI '93 conference on Human factors in computing systems
%C New York, NY, USA
%D 1993
%I ACM
%K evaluation imported inspection model roi usability usability_testing
%P 206--213
%R http://doi.acm.org/10.1145/169059.169166
%T A mathematical model of the finding of usability problems
%U http://portal.acm.org/citation.cfm?id=169166&dl=ACM&coll=portal&CFID=60015656&CFTOKEN=56411871
%X For 11 studies, we find that the detection of usability problems as a function of number of users tested or heuristic evaluators employed is well modeled as a Poisson process. The model can be used to plan the amount of evaluation required to achieve desired levels of thoroughness or benefits. Results of early tests can provide estimates of the number of problems left to be found and the number of additional evaluations needed to find a given fraction. With quantitative evaluation costs and detection values, the model can estimate the numbers of evaluations at which optimal cost/benefit ratios are obtained and at which marginal utility vanishes. For a “medium” example, we estimate that 16 evaluations would be worth their cost, with maximum benefit/cost ratio at four.
%@ 0-89791-575-5
@inproceedings{169166,
abstract = {For 11 studies, we find that the detection of usability problems as a function of number of users tested or heuristic evaluators employed is well modeled as a Poisson process. The model can be used to plan the amount of evaluation required to achieve desired levels of thoroughness or benefits. Results of early tests can provide estimates of the number of problems left to be found and the number of additional evaluations needed to find a given fraction. With quantitative evaluation costs and detection values, the model can estimate the numbers of evaluations at which optimal cost/benefit ratios are obtained and at which marginal utility vanishes. For a “medium” example, we estimate that 16 evaluations would be worth their cost, with maximum benefit/cost ratio at four.},
added-at = {2008-11-17T18:09:04.000+0100},
address = {New York, NY, USA},
author = {Nielsen, Jakob and Landauer, Thomas K.},
biburl = {https://www.bibsonomy.org/bibtex/2459515412ffb41f79c32287c87edf1a6/ewomant},
booktitle = {CHI '93: Proceedings of the INTERACT '93 and CHI '93 conference on Human factors in computing systems},
description = {A mathematical model of the finding of usability problems},
doi = {http://doi.acm.org/10.1145/169059.169166},
interhash = {4cbc9f215bb6d3a0b90395eb79f232cf},
intrahash = {459515412ffb41f79c32287c87edf1a6},
isbn = {0-89791-575-5},
keywords = {evaluation imported inspection model roi usability usability_testing},
location = {Amsterdam, The Netherlands},
pages = {206--213},
publisher = {ACM},
timestamp = {2008-11-17T18:09:04.000+0100},
title = {A mathematical model of the finding of usability problems},
url = {http://portal.acm.org/citation.cfm?id=169166&dl=ACM&coll=portal&CFID=60015656&CFTOKEN=56411871},
year = 1993
}