Very useful. The ‘subtotal’ is what it says on the tin. The forest plot in the Cochrane Collaboration logo is from one of the first systematic reviews ever published [3]. Figures 5-8 highlight different elements on the forest plot that are worth noting.Figure 5. If these studies are all testing the same intervention, why don’t they get the same results? Let’s have a bit of a look at all the “bumf” so to speak that sits around the forest plot on the graph. Nathan you did a great job. A funnel plot can do that instead. Whereas prophylactic ICD implantation is of significant benefit in ischemic cardiomyopathy patients, the magnitude of absolute benefit in those with nonischemic DCM is relatively small (1.4% per year; cumulative, 7% over 5 years) at best. Observation studies demonstrated that the risk of SCD in this patient population is very low, and the utility of wearable cardioverter defibrillators is very limited and unlikely to be cost effective.Pooled estimate of individual effect sizes of primary studies can be calculated as a weighted mean:Block: The block represents the weighted mean (point estimate) of primary study 95% confidence interval line: The 95% confidence interval line represents the primary study Significance line (line of no effect): The significance line represents outcome variable value neutrality.Meta-analysis weighted mean: The meta-analysis weighted mean vertically represents the weighted mean of effect sizes, obtained by meta-analysis.Pooled estimate: The pooled estimate represents the weighted mean of effect sizes, obtained by meta-analysis. Now, The diamond represents the point estimate and confidence intervals when you combine and average all the individual studies together. It has one line representing each study in the meta-analysis, plotted according to the standardised mean difference (SMD – very roughly, this is the difference between the average score of participants in the intervention group, and the average score of participants in the control group). Let’s try and digest the evidence.The blog explains what we mean by – and how to calculate – ‘sensitivity’, ‘specificity’, ‘positive predictive value’ and ‘negative predictive value’ in the context of diagnosing disease. What does WMD (weighted mean difference) mean?Thanks for the training now I a happy and I can interpret the forest plot.Thank you so much for this insightful tutorial, it really covers a lot, and well.Nathan, thank you so very much for this explanation. Nevertheless, since this patient population has a relatively low mortality rate, the benefit of ICD therapy probably is modest at best. Have a go at interpreting what each study is telling you before looking to the bottom of the webpage for the answer.Figure 4 adds two more studies at the top (have a go at interpreting them) as well as a diamond. You can make a good teacher. Very informative.
Or the statistics being used might be an ‘absolute’ one such as Absolute Risk Reduction (ARR) or Standardised Mean Difference (SMD).

I will reveal the significance of this particular forest plot at the end of the blog!Antenatal corticosteroids for accelerating fetal lung maturation for women at risk of preterm birth
Keep it up! Unfortunately, this is rarely the case. Whilst it is not guaranteed, as a rule of thumb the studies with a Now you have read through the above description, have a look at Study (A) and Study (B) on Figure 3. Conversely, black race and higher NYHA functional class were associated with a lower LVEF at follow-up. By pooling data from several studies, a meta-analysis is a way of overcoming the limitations associated with single, small studies.The plot also provides an indication of the relative The horizontal line running through the point estimate gives an indication of the confidence interval, or the degree of Studies whose point estimate or confidence interval crosses unity (1 on the graph) show no statistical The final key piece of information that a forest plot provides is an indication of the heterogeneity between studies. The horizontal axis usually represents the statistic the studies being profiled show. The rule of thumb is that you want the IHopefully, going through a forest plot from start to finish has helped you understand what makes forest plots tick. Just loved this page. Image from Roberts et al. One of the most popular ways of graphically representing meta-analysis results is the use of a Principles and Practice of Clinical Research (Fourth Edition)Inclusion/Exclusion Criteria, Stratification, and Subgroups – Part IThe database provides a valuable way to verify and validate hypotheses with related data sets.