Predictors of submitting suggestions and their quality were studied in a Dutch company with a well-developed suggestion system (n=207 blue collar workers). A model with person variables (initiative at work, higher order need strength, control aspirations, and interest in work innovation), work characteristics (control and complexity), motives (better work, reward), self-efficacy, and system factors (system inhibitors, system responsiveness, and supervisor support) was developed and tested. They are related to the three process variables, deemed to be important in making a suggestion: having ideas, submitting suggestions and quality of the suggestions. A path analysis revealed that the most important factors related to these process variables were initiative at work, higher order need strength, self-efficacy, expected improvements in work and suggestion inhibitors (negatively). Copyright © 1999 John Wiley & Sons, Ltd.