如果是这样的话,我们可以预料到真正的效果在研究之间存在相当大的异质性(heterogeneity)。所有这些都使人对固定效应模型的有效性产生怀疑。例如,如果一些研究使用了不同类型的治疗方法,那么一种形式比另一种更有效似乎是完全正常的。假设这些差异只是由研究的抽样误差产生的噪音,那就太牵强了。恰恰相反,可能有无数的...
Heterogeneity in meta-analysis refers to the variation in study outcomes between studies. StatsDirect calls statistics for measuring heterogentiy in meta-analysis 'non-combinability' statistics in order to help the user to interpret the results....
每个研究权重是其方差的倒数。由于Q不仅取决于偏差，也取决于权重。也就是说，更小的标准误，也就是有...
Intra-continental heterogeneity in effect size and allele frequency Finally, to assess the level of heterogeneity between various African cohorts we compared the distribution of MAFs and effect size estimates for SNPs that were detected as lead SNPs in the Stage-2 GWAS in the AADM, UGR, DDC, D...
and SNPs with association atP<1 × 10−5were considered to show a suggestive association. Heterogeneity of allelic associations was examined using the Cochran's Q statistic64P<0.05, as well as theI2index65, which indicates the proportion of variance attributable to between-study heterogeneity. M...
meta回归模型会给出参数:R^2 (amount of heterogeneity accounted for),用于量化模型解释的变异百分比。R^2越接近1,则模型拟合良好。 Q:多重meta回归模型是指? A:meta回归模型纳入 ≥1 个预测因子。 Q:多重meta回归模型的问题? A: (1)过拟合:模型与与数据拟合得太近,主要模拟统计噪声 ...
Since the difference between infants’ and adults’ microbiomes may introduce a particularly prominent source of heterogeneity, we also conducted a supplementary analysis, excluding the one infant dataset included in our study (the HE dataset). Overall, this exclusion did not markedly impact our ...
Power calculation for random-effects models further requires a sample size for each individual effect as well as an approximation of the expected heterogeneity between studies. For the sample size input, we used the median sample size in each of our studies. For heterogeneity, we assumed a value...
Heterogeneity The heterogeneity was relatively low in the analysis of the overall change in cough severity (16%; CI 0%; 58%). In order to assess the robustness of conclusions concerning the pooled effect sizes, leave-one-out sensitivity analysis was performed. It found that the study by Lam...
After performing the meta-analysis, variants showing heterogeneity of effect between the two datasets (P < 1 × 10−5) and those in which the minimum/maximum allele frequencies differed by >0.25 were excluded leaving 7,715,762 variants. Eleven loci achieved genome-wide significance (...