Myślę, że cross posiada zwykłe znaczenie.

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Note added at 7 hrs (2017-08-29 01:27:54 GMT)
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Thresholds of any kind are crossed. Here, in a clinical study, a futility criterion is established (for example, the number of deaths); once this criterions is crossed (exceeded = przekroczyć, przewyższyć), the study is interrupted.

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Assessment of futility in clinical trials

Article in Pharmaceutical Statistics 5(4):273-81 · October 2006
DOI: 10.1002/pst.216 · Source: PubMed
Steven Snapinn
1st Steven Snapinn
Mon-Gy Chen
2nd Mon-Gy Chen
Qi Jiang
3rd Qi Jiang
27.47 · Amgen
Tony Koutsoukos
4th Tony Koutsoukos
Abstract
The term 'futility' is used to refer to the inability of a clinical trial to achieve its objectives. In particular, stopping a clinical trial when the interim results suggest that it is unlikely to achieve statistical significance can save resources that could be used on more promising research. There are various approaches that have been proposed to assess futility, including stochastic curtailment, predictive power, predictive probability, and group sequential methods. In this paper, we describe and contrast these approaches, and discuss several issues associated with futility analyses, such as ethical considerations, whether or not type I error can or should be reclaimed, one-sided vs two-sided futility rules, and the impact of futility analyses on power.
https://www.researchgate.net/publication/6670677_Assessment_...
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The DSMB decided to maintain the interim analysis plan as designed, with the caveat that, if the futility boundary was crossed, the magnitude of the apparent qualitative interaction could be considered in the decision to stop the trial for futility.

The pitfalls in making such a design change, based on accruing data, were acknowledged, and the DSMB decided that, as no serious safety concern had been demonstrated and the pre-specified futility boundary had not been crossed, the trial should continue as designed.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4018452/