The practitioner is the working core of Christian Science and the church's most-argued institution. Training is two weeks of Primary class instruction from an authorised teacher; there is no examination in medicine, no licensure, and no ordination. Practitioners advertise in the Christian Science Journal directory, work full time, and charge — historically rates comparable to a physician's visit, and for decades reimbursable by some American insurers and by Medicare and Medicaid for care in Christian Science nursing facilities, provisions that were repeatedly litigated in the 1990s. Christian Science nurses provide non-medical care and do not administer drugs. Church literature states that members are free to choose medical treatment and that many do, particularly for childbirth, broken bones and dentistry; the informal pressure not to is described consistently in accounts by people who have left, and the church's own numbers show the practitioner corps collapsing from 4,965 in the United States in January 1971 to a few hundred.