Preflare values of selected photospheric and coronal measures for 48 flares of sample S​_major. (a) Helicity of the current-carrying field vs. mean characteristic twist parameter, α_total and (b) near-PIL magnetic flux measure, log(R), value vs. the total helicity, H_V for the flares of sample S​_major. (c) Flux-R vs. log ϕ_m, and (d) helicity ratio, |H_J|/|H_V|, vs. flux-normalized flux-R ($R/\stackrel{\sim }{\varphi }$) (events with log(R) < 1 are excluded). Numbers in brackets indicate the ratio of confined to eruptive flares within the tested sample. Blue and red color indicates confined and eruptive flare type, respectively. X-class and M-class flares are shown as stars and circles, respectively.