Complex sentence: First is choosing a "randomization procedure" to generate a random and unpredictable sequence of allocations; this may be a simple random assignment of patients to any of the groups at equal probabilities, or may be complex and adaptive.
Split into simpler sentences: First is choosing a "randomization procedure" to generate a random and unpredictable sequence of allocations. This may be a simple random assignment of patients to any of the groups at equal probabilities, or may be complex and adaptive.