Enhancing online forms: Use format specifications for fields with format restrictions to help respondents

Field format restrictions are often used in online forms to impose certain formatting and content rules on users, such as minimum password length or date entry format. In this study, the question whether and how format restrictions for fields in online forms should be communicated to Internet users was explored. In an online study with n=166 participants, four ways to communicate format restrictions were investigated: (1) no visual format restriction, (2) format examples, (3) format specifications, and (4) both format restrictions (examples and specifications). Results show that providing details of any format restriction to users in advance leads to significantly fewer errors and trials. The most efficient way to communicate field format restrictions to users is by stating the imposed rule (format specification). Providing an additional example neither helps nor constrains users.