* Efficient design of cluster randomized and multicentre trials with unknown intraclass correlation.
- For cluster randomized and multicentre trials evaluating the effect of a treatment on persons nested within clusters, equations have been published to compute the optimal sample sizes at the cluster and person level as a function of sampling costs and intraclass correlation (ICC). Here, optimal means maximum power and precision for a given sampling budget, or minimum sampling costs for a given power and precision. However, the ICC is usually unknown, and the optimal sample sizes depend strongly on this ICC. To overcome this local optimality problem, this study presents Maximin designs (MMDs) based on relative efficiency (RE) and efficiency. These designs perform well over a range of possible ICC values either in terms of RE compared with the locally optimal designs, or in terms of minimum efficiency (maximum variance) of the treatment effect estimator. The use of MMDs is illustrated using information from many cluster randomized trials in primary care. It is concluded that MMDs and the optimal design for an ICC halfway its assumed range are efficient for a range of ICC values and recommendable for practical use. This requires that trial reports mention the study cost per cluster and person.
=>利用, 使う, 利用する, (体, 能力など)を働かす, 使用, 利用法
Overview of noun use
The noun use has 7 senses (first 6 from tagged texts)
1. (90) use, usage, utilization, utilisation, employment, exercise -- (the act of using; "he warned
against the use of narcotic drugs"; "skilled in the utilization of computers")
2. (18) function, purpose, role, use -- (what something is used for; "the function of an auger is to
bore holes"; "ballet is beautiful but what use is it?")
3. (7) use -- (a particular service; "he put his knowledge to good use"; "patrons have their uses")
4. (1) consumption, economic consumption, usance, use, use of goods and services -- ((economics) the
utilization of economic goods to satisfy needs or in manufacturing; "the consumption of energy has
increased steadily")
5. (1) habit, use -- ((psychology) an automatic pattern of behavior in reaction to a specific
situation; may be inherited or acquired through frequent repetition; "owls have nocturnal habits";
"she had a habit twirling the ends of her hair"; "long use had hardened him to it")
6. (1) manipulation, use -- (exerting shrewd or devious influence especially for one's own
advantage; "his manipulation of his friends was scandalous")
7. use, enjoyment -- ((law) the exercise of the legal right to enjoy the benefits of owning
property; "we were given the use of his boat")
Overview of verb use
The verb use has 6 senses (first 3 from tagged texts)
1. (603) use, utilize, utilise, apply, employ -- (put into service; make work or employ for a
particular purpose or for its inherent or natural purpose; "use your head!"; "we only use Spanish at
home"; "I can't use this tool"; "Apply a magnetic field here"; "This thinking was applied to many
projects"; "How do you utilize this tool?"; "I apply this rule to get good results"; "use the
plastic bags to store the food"; "He doesn't know how to use a computer")
2. (12) use, habituate -- (take or consume (regularly or habitually); "She uses drugs rarely")
3. (8) use, expend -- (use up, consume fully; "The legislature expended its time on school
questions")
4. use -- (seek or achieve an end by using to one's advantage; "She uses her influential friends to
get jobs"; "The president's wife used her good connections")
5. practice, apply, use -- (avail oneself to; "apply a principle"; "practice a religion"; "use care
when going down the stairs"; "use your common sense"; "practice non-violent resistance")
6. use -- (habitually do something (use only in the past tense); "She used to call her mother every
week but now she calls only occasionally"; "I used to get sick when I ate in that dining hall";
"They used to vacation in the Bahamas")
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