It says that in many real-life sets of numerical data, the leading digit is likely to be small.
Benford’s law, also known as the Newcomb–Benford law, the law of anomalous numbers, or the first-digit law, is an observation that in many real-life sets of numerical data, the leading digit is likely to be small.[1] In sets that obey the law, the number 1 appears as the leading significant digit about 30% of the time, while 9 appears as the leading significant digit less than 5% of the time. Uniformly distributed digits would each occur about 11.1% of the time.[2] Benford’s law also makes predictions about the distribution of second digits, third digits, digit combinations, and so on.