Socioenergetics

Romana II noted that, in terms of applied socioenergetics, the "vampire planet" was losing its grip on level-two development and that a society that evolved backwards must be subject to powerful forces restraining it. (TV: State of Decay)

The Eighth Doctor admitted that the Time Lords weren't concerned with the details when it came to development classification, as the planet Cosca possessed a "level 4 society" where feudal knights wielded laser swords and understood interdimensional rifts. (AUDIO: Restoration of the Daleks)

Comparable labels were applied to other level 2, (PROSE: Ghosts of India) level 4, (AUDIO: The Four Doctors) level 5 planets (TV: City of Death onwards) and level 6 planets, (PROSE: Ghosts of India) with other designations including grade 3 planets (TV: The Ribos Operation) and class 3 type planets. (PROSE: The Pit)