Gelman-Rubin convergence statistic for the BEYONDPLANCKTT angular power spectrum, as evaluated from four independent σ_ℓ chains. The various curves show results for different total number of samples included in the analysis. A value lower than 1.01 (dotted line) typically indicates good convergence. Accordingly, BEYONDPLANCK multipoles above ℓ ∼ 800 should be acceptable for parameter estimation. However, in the current paper, we conservatively include only modes ℓ ≤ 600 in the cosmological analysis, see text.