WASHINGTON — Soaring advertising costs in early primary states are compelling major “super PACs” to realign their tactics, de-emphasizing costly broadcast commercials in favor of the kind of nuts-and-bolts work that presidential candidates used to handle themselves.

They are overseeing extensive field operations, data-collection programs, digital advertising, email lists, opposition research and voter registration efforts.

The shift away from the broadcast television buys that had been the groups’ main role in past presidential campaigns is among the most significant developments in outside political spending since the Supreme Court’s 2010 Citizens United decision, which paved the way for super PACs. Originally conceived as a vehicle to raise and spend unlimited money on television, the most expensive part of a White House run, the groups now are seeking to relieve campaigns of much of the vital infrastructure that candidates would otherwise have to assemble and manage.

The results of their efforts, which cannot be coordinated directly with the candidates, are unproven. It is not yet known whether field and data efforts spearheaded by outside groups will be as effective as they are in the hands of a candidate.