The impact of sound on film style

This post is the last of three draft papers that apply statistical analysis to questions of film style. This I focus on the impact of sound technology on shot length distributions by examining the change in the median shot length and the interquartile range. You can access the pdf here: Nick Redfern – The impact of sound technology on Hollywood film style, and the abstract is presented below.

Quantitative analyses of the impact of sound technology on shot lengths in Hollywood cinema have claimed that, with the coming of sound, the mean shot length increased from ~5s to ~11s, and that this indicates a major change in film style as cutting rates slowed. However, the mean shot length is not a robust statistic of film style due to the positive skew of the data and the presence of outlying data points in shot length distributions. The median shot length is shown to be a more robust statistic unaffected by shape of shot length distributions, and the impact of sound technology on Hollywood is analysed through looking at the median shot lengths of silent films produced between 1920 and 1928 (n = 20, median = 4.4s [95.86% CI: 3.7, 5.1]) and sound films produced from 1929 to 1931 (n = 30, median = 6.9s [95.72% CI: 5.9, 8.7]). The results show that there is an increase in shot lengths in the early sound era (Mann-Whitney U = 33.5, p = <0.0001, PS = 0.0558), but that this change is much less than that described by studies using the mean shot length (HLΔ = 2.9s [95% CI: 1.8, 4.1]). Looking at the interquartile ranges of the silent films (median = 4.8s [95.86% CI: 4.3, 5.7]) and the sound films (median = 10.7s [95.72% CI: 8.8, 12.1]), we see that there is an increase by HLΔ = 5.5 seconds (95% CI: 4.1, 7.1), indicating that shot lengths in sound films show greater variation than those of the silent era (Mann-Whitney U = 4, p = <0.0001, PS = 0.0067).

As before, I’ll leave this up for a while before submitting it to a journal (if I can find one), so feel free to comment.

UPDATE (07/07/2010): this paper has been updated to take into account a flaw in one of the data sets used, and this has led to a minor revision of the results. The figures for U and PS for the difference between the median shot lengths have both been revised up by a factor of 1/600, so that U is now 33.5 and not 32.5, and PS = 0.0558 instead of 0.0542. The value of HLΔ for the interquartile ranges has been revised down from 5.6s to 5.5s.