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analyses:berkey1995 [2021/10/06 15:48] – Wolfgang Viechtbaueranalyses:berkey1995 [2022/08/03 11:16] – Wolfgang Viechtbauer
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 dat.bcg dat.bcg
 </code> </code>
-The contents of the dataset are: +The contents of the dataset are:
 <code output> <code output>
    trial               author year tpos  tneg cpos  cneg ablat      alloc    trial               author year tpos  tneg cpos  cneg ablat      alloc
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 Model Results: Model Results:
  
-estimate      se     zval    pval    ci.lb    ci.ub  +estimate      se     zval    pval    ci.lb    ci.ub 
- -0.5429  0.1842  -2.9474  0.0032  -0.9040  -0.1819  ** + -0.5429  0.1842  -2.9474  0.0032  -0.9040  -0.1819  **
  
 --- ---
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 These results match exactly what Berkey et al. (1995) report on page 408: The amount of heterogeneity ('between-trial variance') is estimated to be $\hat{\tau}^2 = 0.268$ and the pooled estimate is $\hat{\mu} = -0.5429$ with a standard error of $SE[\hat{\mu}] = 0.1842$. These results match exactly what Berkey et al. (1995) report on page 408: The amount of heterogeneity ('between-trial variance') is estimated to be $\hat{\tau}^2 = 0.268$ and the pooled estimate is $\hat{\mu} = -0.5429$ with a standard error of $SE[\hat{\mu}] = 0.1842$.
  
-==== Mixed-Effects Model ====+==== Mixed-Effects Meta-Regression Model ====
  
-A mixed-effects model with absolute latitude as moderators (centered at 33.46 degrees) can be fitted with:+A mixed-effects meta-regression model with absolute latitude as moderators (centered at 33.46 degrees) can be fitted with:
 <code rsplus> <code rsplus>
 res.ME <- rma(yi, vi, mods=~I(ablat-33.46), data=dat, method="EB") res.ME <- rma(yi, vi, mods=~I(ablat-33.46), data=dat, method="EB")
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 Model Results: Model Results:
  
-                  estimate      se     zval    pval    ci.lb    ci.ub  +                  estimate      se     zval    pval    ci.lb    ci.ub 
-intrcpt            -0.6303  0.1591  -3.9630  <.0001  -0.9421  -0.3186  ***  +intrcpt            -0.6303  0.1591  -3.9630  <.0001  -0.9421  -0.3186  *** 
-I(ablat - 33.46)   -0.0268  0.0110  -2.4294  0.0151  -0.0484  -0.0052    * +I(ablat - 33.46)   -0.0268  0.0110  -2.4294  0.0151  -0.0484  -0.0052    *
  
 --- ---
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 <code output> <code output>
         df     AIC     BIC    AICc   logLik    LRT   pval      QE  tau^2      R^2         df     AIC     BIC    AICc   logLik    LRT   pval      QE  tau^2      R^2
-Full     3 29.3011 30.9960 31.9678 -11.6506               35.8827 0.1572         +Full     3 29.3011 30.9960 31.9678 -11.6506               35.8827 0.1572
 Reduced  2 32.2578 33.3877 33.4578 -14.1289 4.9566 0.0260 85.8625 0.2682 41.3844% Reduced  2 32.2578 33.3877 33.4578 -14.1289 4.9566 0.0260 85.8625 0.2682 41.3844%
 </code> </code>
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 </code> </code>
  
-==== Fixed-Effects Model ====+==== Fixed-Effects Meta-Regression Model ====
  
-The results from a fixed-effects model with absolute latitude as the predictor can be obtained with:+The results from a fixed-effects meta-regression model with absolute latitude as the predictor can be obtained with:
 <code rsplus> <code rsplus>
 res.FE <- rma(yi, vi, mods=~I(ablat-33.46), data=dat, method="FE") res.FE <- rma(yi, vi, mods=~I(ablat-33.46), data=dat, method="FE")
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 Model Results: Model Results:
  
-                  estimate      se     zval    pval    ci.lb    ci.ub  +                  estimate      se     zval    pval    ci.lb    ci.ub 
-intrcpt            -0.5949  0.0696  -8.5462  <.0001  -0.7314  -0.4585  ***  +intrcpt            -0.5949  0.0696  -8.5462  <.0001  -0.7314  -0.4585  *** 
-I(ablat - 33.46)   -0.0282  0.0040  -7.0696  <.0001  -0.0360  -0.0204  *** +I(ablat - 33.46)   -0.0282  0.0040  -7.0696  <.0001  -0.0360  -0.0204  ***
  
 --- ---
-Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1 +Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
 </code> </code>
  
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 </code> </code>
 <code output> <code output>
-  pred ci.lb ci.ub  +  pred ci.lb ci.ub 
-1 0.55  0.48  0.63 +1 0.55  0.48  0.63
 2 0.43  0.36  0.52 2 0.43  0.36  0.52
 </code> </code>
analyses/berkey1995.txt · Last modified: 2022/10/19 18:55 by Wolfgang Viechtbauer