Some underwriting guidelines are more stringent for some types of groups than others. For example, antiselection by individual group members is much more likely to occur in association groups in which group membership is voluntary than in employer-employee groups. AS a result, insurance companies often impose more stringent underwriting requirements on association group than on employer-employee groups. An insurer might be willing to issue an employer-employee group insurance policy to a group with as few as 10 members, but it might refuse to issue an association group policy covering fewer than 50 association members.