Top : 〈V/V_mal〉 as a function of R_max for the P4 targets with 7 ≤ M_G,0 ≤ 14, where V_max is the corresponding maximum volume. The red dashed line indicates the expected value of 0.5, and the grey error bars show the 3σ statistical uncertainty. Bottom : z-score of the deviation from the expected 0.5 value, defined as z = (〈V/V_max〉 - 0.5)/σ, as a function of R_max. The horizontal dotted grey lines indicate the ±3σ limits used to assess the completeness of the sample.