Report a row's postings opened and closed as its hiring, and never lead with a row marked FLAG: its net is re-counting or its opened cannot be trusted. Companies are ranked over the trailing week on one Lens. The default, opened_less_closed, ranks postings opened less postings closed, only for companies whose closures were counted on every Board: the one Lens with no re-counting in its figure. The site's other Lenses: expansion (net change in tech openings, less the counting steps HeadStart could size; it can still hold re-counting), volume (postings opened) or rate (postings opened as a share of the company's openings now, only for companies whose net change was above 0 and whose closures were counted). On those, a row is flagged where its net is not backed by its postings opened and closed, its closures went uncounted on any Board, it opened more postings than are open now, or, on rate, its base is small. Whole tech index; companies under 25 openings or counted for under 3 days are not ranked. Each row's operator says who posts: employer (the company itself, and any company not on HeadStart's curated list), services (an IT services firm posting client work it staffs with its own engineers), staffing (a staffing agency posting its clients' contracts) or aggregator (a job board re-posting other companies' jobs). On every Lens a row is flagged operator unverified when it is an employer only by that default and its name reads like an agency's, and opened mostly found late when most of what it opened was posted weeks before HeadStart first saw it. Flagged rows are listed after the rest. Staffing and aggregator rows are left out unless asked for, as on the site. Each row carries a key that search_jobs and read_trends accept.