allocation concealment造句

• Some standard methods of ensuring allocation concealment include sequentially numbered, opaque, sealed envelopes ( SNOSE ); sequentially numbered containers; pharmacy controlled randomization; and central randomization.
• Non-random " systematic " methods of group assignment, such as alternating subjects between one group and the other, can cause " limitless contamination possibilities " and can cause a breach of allocation concealment.
• A 2008 systematic review of magnet therapy for all indications found insufficient evidence to determine whether magnet therapy is effective for pain relief, Both reviews reported that small sample sizes, inadequate randomization, and difficulty with allocation concealment all tend to bias studies positively and limit the strength of any conclusions.
• First is choosing a " randomization procedure " to generate an unpredictable sequence of allocations; this may be a simple random assignment of patients to any of the groups at equal probabilities, may be " restricted, " or may be " adaptive . " A second and more practical issue is " allocation concealment ", which refers to the stringent precautions taken to ensure that the group assignment of patients are not revealed prior to definitively allocating them to their respective groups.