Summarizes participant flow and disposition in clinical trials,
including CONSORT-style randomized controlled trials, parallel-group,
crossover, cluster randomized, and multi-arm trials. Provides functions
for screening failures, exclusions and reasons, allocation, follow-up,
loss to follow-up, withdrawals, intention-to-treat and per-protocol
populations, and participant-disposition summaries. The methods are
based on established principles for reporting participant flow and
disposition in randomized trials; see Schulz et al. (2010)