validation of multiple check boxes for returned array in query

I'm trying to check proper number of check boxes for a question that are selected.

jQuery script is:

$.validator.addMethod("q3", function(value, elem, param) {
    if($(".q3:checkbox:checked").length > 3){
        return true;
    }
    else 
    {
        return false;
    }
}, "You must select at least 4!");

and on the actual input I have:

<input class='{roles: true}' type="checkbox" name="q3[]" value="a"/>

Am I in left field with this or missing something simple?