The expectation norm of comparison for Information Systems SERVQUAL has been challenged
on both conceptual and empirical grounds, drawing into question the instrument's practical
value. To address the criticism that the original IS SERVQUAL's expectation measure
is ambiguous, we test a new set of scales that posits that service expectations exist
at two levels which IS customers use as a basis to assess IS service quality: (1)
desired service: the level of IS service desired, and (2) adequate service: the minimum
level of IS service customers are willing to accept. Defining these two levels is
a zone of tolerance (ZOT) that represents the range of IS service performance a customer
would consider satisfactory. In other words, IS customer service expectations are
characterized by a range of levels, rather than a single expectation point. This research
note adapts the ZOT and the generic operational definition from marketing to the IS
field, assessing its psychometric properties. Our findings conclude that the instrument
shows validity of a four-dimension IS ZOT SERVQUAL measure for desired, adequate,
and perceived service quality levels, identifying 18 commonly applicable question
items. This measure addresses past criticism while offering a practical diagnostic
tool.
