So much for plain language: An analysis of the accessibility of U.S. federal laws over time.

Over the last 50 years, there have been efforts on behalf of the U.S. government to simplify legal documents for society at large. However, there has been no systematic evaluation of how effective these efforts-collectively referred to as the "plain-language movement"-have been. Here we report the results of a large-scale longitudinal corpus analysis (n ≈ 225 million words), in which we compared every law passed by congress with a comparably sized sample of English texts from four different baseline genres published during approximately the same time period. We also compared the entirety of the U.S. Code (the official compilation of all federal legislation currently in force) with a large sample of recently published texts from six baseline genres of English. We found that laws remain laden with features associated with psycholinguistic complexity-including center-embedding, passive voice, low-frequency jargon, capitalization, and sentence length-relative to the baseline genres of English, and that the prevalence of most of these features has not meaningfully declined since the initial onset of the plain-language efforts. These findings suggest top-down efforts to simplify legal texts have thus far remained largely ineffectual, despite the apparent tractability of these changes, and call into question the coherence and legitimacy of legal doctrines whose validity rests on the notion of laws being easily interpretable by laypeople. (PsycInfo Database Record (c) 2024 APA, all rights reserved).