I find both approaches combined to be most effective. People do show up more often if you knock out barriers. This leaves the common preconceptions, expectations, and do on that can reduce entry attempts if its employment or sustained effort if it's something like getting women to learn IT stuff or enjoy computers. That said, I believe it's important that the situation stays meritocratic where women know they earned their place based on skill. It's why I favor mentoring, blind auditions, women-oriented events in parallel to business/projects, and so on. They get increase diversity without problems from approaches like pure quotas or focusing on employee gender more than skill in how they're treated.