Providing Advisory Notices for UNIX Command Users: Design, Implementation, and Empirical Evaluations

UNIX Notices (UN) was developed to study the problems in providing advice tousers of complex systems. The issues studied were: what, when, and how
to present the advice.
The first experiment with 24 subjects examined how different presentation
styles affect the
effectiveness of UNs advice. The three presentation styles studied were:
notice appears in separate window; notice appears only on request;
notice appears in users window immediately. The results
showed that the third style was significantly more effective than the first style. Furthermore, the
results indicated that the most effective presentation method is also the most disruptive.
The second experiment with 29 subjects studied how delay in the advice feedback affects the
performance of UN. The treatments were: immediate feedback, feedback at end of session, and no
feedback. Over a period of 6 weeks, the commands entered by the subjects were logged and
studied. The results showed that immediate feedback caused subjects to repeat significantly fewer
inefficient command sequences. However, immediate feedback and feedback at end of session
may have given subjects a negative feeling towards UNIX.
(Also cross-referenced as CAR-TR-651)