Fracture mechanics tests of welds and ferritic steels in the brittle to ductile region often show a phenomenon called pop-in, a process of trigger and arrest of a brittle crack. Regarding pop-in initiation as a critical event results in too conservative values of fracture toughness. Different pop-in treatment proposals taken from the literature are analyzed in this paper. The degree of conservatism of the pop-in assessment procedures issued in some fracture toughness test standards is also analyzed. An alternative proposal for the analysis of the pop-in significance in SENB CTOD tests is introduced. This method is based on the change in elastic compliance, and it allows the evaluation of any pop-in, even those that are preceded by ductile crack growth or previously ignored pop-ins. The relaxation of the maximum pop-in crack extension implicit in both ASTM and BSI procedures (Δa p < 2%b 0 ) by the Willoughby criterion of Δa p < 4%b 0 is also proposed.