Usable error message presentation in the World Wide Web: Do not show errors right away

Online form validation can be performed in several ways. This article discusses two empirical studies with 77 and 90 participants, which have found evidence that the best way of presenting error messages is to provide the erroneous fields after users have completed the whole form. Immediate error feedback recommended by the International Organization for Standardization (ISO) showed the worst performance in these studies. Where presented with immediate feedback, users often simply ignored the messages on the screen and continued completing the form as if nothing happened. These results lead to the postulation of the "Modal Theory of Form Completion": Users are in either "Completion" or "Revision Mode" when filling out online forms. These modes affect the users` way of interaction with the system: During Completion Mode the users` disposition to correct mistakes is reduced, therefore error messages are often ignored. (c) 2007 Elsevier B.V. All rights reserved.