I have a good record on recommendation letters for grad school candidates always centered on stories of how a candidate has an insatiable thirst for the truth and challenges the status quo to satisfy it. I also make it a point on how this improves debate and understanding within their team improving on overall dynamics. Of course this is in the realm of high-tech engineering.<p>I think that probably does translate to assertive qualities, but in a sense this is what grad school is about, the search for truth and how a candidate will improve the experience for their fellow students and the faculty...<p>The important thing in effective recommendation letters and applications in general is to know what the evaluators are looking for and speak to it. If they are looking for communal cultural fit, by all means speak to it, but if not, it is a wasted opportunity.