The largest investigation of digit ratio (2D:4D), the BBC Internet Study, reported on finger lengths measured by participants themselves, yet data validating this technique are scarce and the reliability has been questioned. The current study aimed to calculate reliability and repeatability statistics for self-measured 2D:4D and to examine the correlations with researcher-measures. One hundred and seventy-eight undergraduate psychology students attending a practical class self-measured their finger lengths with rulers; a researcher using digital Vernier calipers measured the second and fourth fingers of a random sub-sample (n = 97). Reliability and repeatability of self-measured 2D:4D were high, as were correlations with researcher-measurements. In each case, lower values were observed for the right-left difference in 2D:4D (D[R-L]). Self-measured L2D:4D and M2D:4D were significantly higher than the equivalent researcher measurements, suggesting that direct comparison could be problematic. Self-measurements and directly made researcher-measurements of 2D:4D are strongly correlated, though self-measured D[R-L] is unreliable.

中文翻译：

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自我测量和研究人员测量的数字比率（2D：4D）的比较。

BBC互联网研究是对数字比例最大的调查（2D：4D），报告的对象是参与者自己测量的手指长度，然而，验证该技术的数据很少，并且可靠性也受到质疑。当前的研究旨在计算自测2D：4D的可靠性和可重复性统计数据，并研究与研究人员测度的相关性。参加实践课的一百七十八名心理学专业的本科生用尺子来测量他们的手指长度；一位使用数字游标卡尺的研究人员测量了随机子样本（n = 97）的第二根和第四根手指。自我测量的2D：4D的可靠性和可重复性很高，与研究人员的测量结果也相关。在每种情况下，在2D：4D（D [RL]）中观察到的左-右差值较低。自我测量的L2D：4D和M2D：4D显着高于同等的研究人员测量，这表明直接比较可能会出现问题。2D：4D的自我测量和直接进行的研究人员测量密切相关，尽管自我测量的D [RL]不可靠。