1School of Medicine, Flinders University, Bedford Park.
2Department of Neurosurgery, Royal Adelaide Hospital, Adelaide.
J Neurosurg. 2019 Feb 8;132(2):662-670. doi: 10.3171/2018.8.JNS172897. Print 2020 Feb 1.
The objective of this study was to evaluate the trends in reporting of p values in the neurosurgical literature from 1990 through 2017.
All abstracts from the Journal of Neurology, Neurosurgery, and Psychiatry (JNNP), Journal of Neurosurgery (JNS) collection (including Journal of Neurosurgery: Spine and Journal of Neurosurgery: Pediatrics), Neurosurgery (NS), and Journal of Neurotrauma (JNT) available on PubMed from 1990 through 2017 were retrieved. Automated text mining was performed to extract p values from relevant abstracts. Extracted p values were analyzed for temporal trends and characteristics.
The search yielded 47,889 relevant abstracts. A total of 34,324 p values were detected in 11,171 abstracts. Since 1990 there has been a steady, proportionate increase in the number of abstracts containing p values. There were average absolute year-on-year increases of 1.2% (95% CI 1.1%-1.3%; p < 0.001), 0.93% (95% CI 0.75%-1.1%; p < 0.001), 0.70% (95% CI 0.57%-0.83%; p < 0.001), and 0.35% (95% CI 0.095%-0.60%; p = 0.0091) of abstracts reporting p values in JNNP, JNS, NS, and JNT, respectively. There have also been average year-on-year increases of 0.045 (95% CI 0.031-0.059; p < 0.001), 0.052 (95% CI 0.037-0.066; p < 0.001), 0.042 (95% CI 0.030-0.054; p < 0.001), and 0.041 (95% CI 0.026-0.056; p < 0.001) p values reported per abstract for these respective journals. The distribution of p values showed a positive skew and strong clustering of values at rounded decimals (i.e., 0.01, 0.02, etc.). Between 83.2% and 89.8% of all reported p values were at or below the "significance" threshold of 0.05 (i.e., p ≤ 0.05).
Trends in reporting of p values and the distribution of p values suggest publication bias remains in the neurosurgical literature.
本研究旨在评估 1990 年至 2017 年神经外科学文献中 p 值报告的趋势。
检索 1990 年至 2017 年在 PubMed 上可获取的《神经病学、神经外科学与精神病学杂志》（JNNP）、《神经外科学杂志》（JNS）合集（包括《神经外科学杂志：脊柱》和《神经外科学杂志：儿科》）、《神经外科学》（NS）和《神经创伤杂志》（JNT）的所有摘要。采用自动化文本挖掘从相关摘要中提取 p 值。分析提取的 p 值以评估时间趋势和特征。
检索得到 47889 篇相关摘要。在 11171 篇摘要中发现了 34324 个 p 值。自 1990 年以来，包含 p 值的摘要数量呈稳定的比例增长。每年的平均绝对增长率分别为 1.2%（95%置信区间 1.1%-1.3%；p<0.001）、0.93%（95%置信区间 0.75%-1.1%；p<0.001）、0.70%（95%置信区间 0.57%-0.83%；p<0.001）和 0.35%（95%置信区间 0.095%-0.60%；p=0.0091），分别对应 JNNP、JNS、NS 和 JNT 杂志中报告 p 值的摘要比例。每年的平均增长率也分别为 0.045（95%置信区间 0.031-0.059；p<0.001）、0.052（95%置信区间 0.037-0.066；p<0.001）、0.042（95%置信区间 0.030-0.054；p<0.001）和 0.041（95%置信区间 0.026-0.056；p<0.001），即这四个期刊的每篇摘要报告的 p 值。p 值的分布呈正偏态，且在四舍五入的小数（即 0.01、0.02 等）处呈强聚类。所有报告的 p 值中，有 83.2%至 89.8%在或低于“显著性”阈值 0.05（即 p≤0.05）。
p 值报告的趋势和 p 值的分布表明，神经外科学文献中仍存在发表偏倚。
