The readability of expert reports for non-scientist report-users: reports of forensic comparison of glass

Scientific language contains features that may impede understanding for non-scientists. Forensic scientists' written reports are read by police, lawyers, and judges, and thus assessment of readability is warranted. Past studies of readability differed in background theory and approach, but analysed one or more of: content and sequence; language; and format. Using a holistic approach, we assessed the readability of expert reports (n=78) of forensic glass comparison from 7 Australian jurisdictions. Two main audiences for reports were relevant: police and the courts. Reports for police were presented either as a completed form or as a brief legal-style report. Reports for court were less brief and used either legal or scientific styles, with content and formatting features supporting these distinctions. Some jurisdictions prepared a single report to satisfy both the courts and police. In general, item list, analytical techniques, results, notes on interpretation, and conclusions were included in reports of all types. However, some reports omitted analytical techniques, and results and conclusions were sometimes combined. According to Flesch Reading Ease, language was difficult, with a Flesch-Kincaid grade level of university undergraduate. Sentences were long and contained undefined specialist terms. Information content per clause (lexical density), was typically high, as for other scientific texts. Uncertainty was expressed differently by jurisdiction. Reports from most jurisdictions were cluttered in appearance, with single-line spacing, narrow margins, and gridlines in tables. Simple suggestions, based on theory and past research, are provided to assist scientists to enhance the readability of expert reports for non-scientists.