Article II, Section 2 of the U.S. Constitution indicates "The President shall have power to fill up all vacancies that may happen during the recess of the Senate, by granting commissions which shall expire at the end of their next session."
Scott E. Graves and Robert M. Howard
Political Research Quarterly, Vol. 63, No. 3 (Sep. 2010), pp. 640-653
Examines every judicial recess appointment from 1789 to 2004.
Pamela C. Corley
Presidential Studies Quarterly, Vol. 36, No. 4 (Dec. 2006), pp. 670-680
Examines the conditions under which a President is likely to use a recess appointment with an emphasis on appointments to independent agencies.
Ryan C. Black, Anthony J. Madonna, Ryan J. Owens and Michael S. Lynch
Political Research Quarterly, Vol. 60, No. 4 (Dec. 2007), pp. 645-654
Includes a data set of every civilian nomination and recess appointment from 1987 to 2004.
Christina M. Kinane (2021). American Political Science Review., Vol. 115, No. 2 (2021), pp. 599-614.
Uses a dataset of vacancies across 15 executive departments from 1977 to 2016 to evaluate informal appointment power strategies.