ELIZA

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280501 occurrences (No.89 in the rank) during 5 years in the PubMed. [no cache] 500 found

298) We then evaluate the efficiency of each allocation and show that the popular balanced design is optimal or highly efficient for a range of research questions except for contrasting one treatment arm with all other treatment arms.

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PMID:24030312 DOI:10.1177/0962280213502145

2015 Statistical methods in medical research

* Efficient treatment allocation in two-way nested designs.

- Cluster randomized and multicenter trials sometimes combine two treatments A and B in a factorial design, with conditions such as A, B, A and B, or none. This results in a two-way nested design. The usual issue of sample size and power now arises for various clinically relevant contrast hypotheses. Assuming a fixed total sample size at each level (number of clusters or centers, number of patients), we derive the optimal proportion of the total sample to be allocated to each treatment arm. We consider treatment assignment first at the highest level (cluster randomized trial) and then at the lowest level (multicenter trial). We derive the optimal allocation ratio for various sets of clinically relevant hypotheses. We then evaluate the efficiency of each allocation and show that the popular balanced design is optimal or highly efficient for a range of research questions except for contrasting one treatment arm with all other treatment arms. We finally present simple equations for the total sample size needed to test each effect of interest in a balanced design, as a function of effect size, power and type I error α. All results are illustrated on a cluster-randomized trial on smoking prevention in primary schools and on a multicenter trial on lifestyle improvement in general practices.

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(2)40 on	(15)6 by	(28)3 directions	(41)2 involving
(3)36 is	(16)6 to	(29)3 evidence	(42)2 participants,
(4)27 and	(17)5 projects	(30)3 have	(43)2 progress
(5)25 has	(18)4 culture	(31)3 method	(44)2 sponsored
(6)14 in	(19)4 design	(32)3 results	(45)2 the
(7)12 was	(20)4 findings	(33)3 shows	(46)2 topic
(8)11 are	(21)4 needs	(34)3 study	(47)2 towards
(9)11 should	(22)4 project	(35)3 will	(48)2 trends
(10)9 into	(23)4 questions	(36)2 efforts	(49)2 using
(11)9 with	(24)4 regarding	(37)2 examined	(50)2 we
(12)8 studies	(25)3 &	(38)2 focus	(51)2 work
(13)8 suggests	(26)3 aimed	(39)2 for

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--- WordNet output for research --- =>調査する, 研究(する), 探求, 調査, 捜索, 研究する Overview of noun research The noun research has 2 senses (first 2 from tagged texts) 1. (46) research -- (systematic investigation to establish facts) 2. (6) inquiry, enquiry, research -- (a search for knowledge; "their pottery deserves more research than it has received") Overview of verb research The verb research has 2 senses (first 1 from tagged texts) 1. (1) research -- (attempt to find out in a systematically and scientific manner; "The student researched the history of that word") 2. research, search, explore -- (inquire into; "the students had to research the history of the Second World War for their history project"; "He searched for information on his relatives on the web"; "Scientists are exploring the nature of consciousness") --- WordNet end ---