Statistical style analysis method

In his Film Quarterly essay 'Statistical Style Analysis of Motion Pictures' (1974), Barry Salt aimed to identify the individual style of a director by systematically collecting data on the formal parameters of films, particularly those formal parameters that are most directly under the director's control, including:

• duration of the shot (including the calculation of average shot length, or ASL);

• camera movement;

• strength of the cut (measured in terms of the spatio-temporal displacement from one shot to the next).

Salt collected data from these parameters by laboriously going through the film shot by shot. For most of his analyses, he in fact collected data on all the shots that appear in the first 30 minutes of each film, because this is a representative sample from the film. We shall employ (and test the viability of) this practice in our statistical style analysis of The English Patient in section 3.6. Salt is also interested in combining the results of each parameter. For example, he argues that it would be useful to combine 'duration of the shot' with 'shot scale' for each film (or indeed, a director's entire output), in order to determine 'the relative total times spent in each type of shot' (Salt 1974:15), 'giving an indication of the director's preference for the use of that type of shot' (p. 15). So, a director may use close-ups for a total of 20 minutes during a film, long shots for 30 minutes, and so on.

After analysing a sample of films from four directors, Salt finds that both shot scale and ASL are significant and defining characteristics of a director's style. (Calculating the ASL involves dividing the duration of the film by the number of shots.) However, the distribution of shot scale is similar for the four directors he analyses.

In a statistical style analysis of the films of Max Ophuls (Salt 1992: ch. 22), Salt uses standard stylometric tests to analyse the distribution of stylistic parameters in each film. First, histograms, or bar charts, represent the number of each shot type in each film (the number of close-ups, long shots, etc.). Second, he takes equal lengths of film, calculates the expected number of shots and shot types in each section, and then counts the actual number of shots and shot types in that section, to determine whether they conform to the average (the mean) or deviate from it. There are several ways to select the equal section intervals:

1. Salt recommends intervals of one minute (i.e. 100-ft intervals on 35mm film).

2. If calculating shot types one can define the intervals in terms of number of shots (e.g. 50) and calculate the expected number of shot types, and the actual number of shot types.

3. Take the ASL of the whole film, and then analyse it scene by scene (each scene is defined in terms of spatio-temporal unity and in terms of events). Work out the expected number of shots and shot types for each scene, and count the actual number of shots. If the ASL is ten seconds, and the scene lasts two minutes, the expected number of shots for that scene is 12.

In his analysis of Letter from an Unknown Woman, Salt notes:

For instance, in scene 1 five shots would be expected if the cutting were even throughout every part of the film, but in fact there are only three shots. Contrariwise, in scene no. 5, while only seven shots would be expected, there are actually fourteen.

This type of analysis can also be applied to the expected number and the actual number of shot types in each scene and the number of shot types. Salt's analysis of Ophuls' film Caught shows how this information can be useful in analysing a film's style:

Caught is the first Max Ophuls film in which there is a very definite reduction in the amount of variation in Scale of Shot and cutting rate from scene to scene, and this becomes very apparent if a breakdown into 100ft sections is made on a 35mm. print. After the point in the film at which Leonora has married Smith-Ohlrig and been left: alone in his mansion, we have for the next half hour of screen time very little departure from the average Scale of Shot distribution, and the cutting rate is also very steady for lengths of several minutes at a time, despite the occurrence of scenes of quite varied dramatic nature. It is only in the last 12 minutes of the film, when the most dramatic twitches of the plot take place, that there are any strong deviations from the norms.

Salt is able to determine not only how the shot lengths and scales are distributed across the whole film, but also how this film compares to Ophuls' other films ('Caught is the first Max Ophuls film in which there is a very definite reduction in the amount of variation in Scale of Shot and cutting rate from scene to scene'). Salt develops this historical analysis by considering Ophuls' later films, and notes that Ophuls pares down variation in shot scale even more (relying more and more on the medium long shot), and using longer and longer takes, often combined with extensive camera movements.

For example, in La Ronde, with the scene between The Young man and The Chambermaid we get, after the first 11 shots, long strings of up to 10 shots each with the same camera distance in every shot. Most of these are also in the Medium or medium Long Shot scale, and the film continues in the same manner after this scene. At one point there is a string of 15 consecutive close ups, which is the sort of thing that just did not happen in other people's films in the same period, as a litde checking will show.

In summary, statistical style analysis is a very precise tool for determining both the stability and the change in style that takes place across a film-maker's career. Statistical style analysis focuses the research on how films are put together, rather than how they are perceived or comprehended.

Barry Salt carried out his statistical analysis by hand, which limited the types of test he could perform on the data he collected. With the exponential growth in computer technology and software over the last decade, statistical style analysis can now be carried out using computer technology and powerful software programs. In the following analysis of The English Patient, data was still collected by hand, but it was then entered into the software program SPSS for Windows (Statistical Package for Social Scientists). SPSS is a spreadsheet program, with rows and columns. In film analysis, each row (which is automatically numbered) represents a shot, and each column represents a parameter of that shot. The parameters recorded include: shot scale, shot length, camera movement, direction of moving camera, and camera angle. Once the data has been entered, it can be represented both numerically and visually, and numerous statistical tests can then be performed on it.

The following analysis of The English Patient will consist of both the visual and numerical representation of data (particularly bar graphs and frequency and percentage tables). Then a few simple statistical tests will be applied: measure of the mean or average shot length; measure of the standard deviation of shot length; and the skewness of the values for shot length and shot scale. (The results will also be compared to a similar analysis of Jurassic Park.) The mean is a measure of central tendency, of the average value of a range of values. Standard deviation is the reverse of measuring the mean, for it is a measure of dispersion, or distribution spread of values, around the mean; if the value of the standard deviation is large, this means that the values are widely distributed. Skewness measures the degree of non-symmetrical distribution of values around the mean. If the values are perfectly distributed, then the skewness value will be zero. If more of the values are clustered to the left of the mean (i.e. if their value is less than the mean), then the distribution is positively skewed. If the values are clustered to the right of the mean, the distribution is negatively skewed.

These tests properly apply only to ratio data (where zero is an absolute value - zero weight, zero time, etc.). Only shot length is, strictly speaking, ratio data. In the shot scale, numbers have been assigned to the categories, which means that they constitute a nominal scale (Very Long Shot is 7, but there is not reason why it couldn't be 1). However, by using the nominal scale consistently (1 = big close up, 2 = close up, 3 = medium close up, etc.) the norm, standard deviation, and skewness do at least have some heuristic value.

Other stylistic issues that can be raised (but won't be for this exercise) is to enter the number of scenes in the SPSS program, and then calculate the average number of shots per scene, and therefore calculate the expected number of shots per scene, and the actual number. Other useful data can be collected on positional reference (for example, what position do close ups typically take in a film? - the first, second, third shot?) or contextual reference (do close ups usually follow long shots?). Percentiles are also a useful tool. They measure the number of variables at regular intervals of a text. For example, at every 5 per cent, count the number of variables (e.g. close-ups) in the film. This will reveal whether the variables are evenly distributed throughout the film, or concentrated in a particular part of it. One of the most interesting tests, however, is to determine the correlation between variables. For example, what is the correlation between shot length and shot scale? We would expect some correlation, because close-ups usually appear on screen only for a short time, whereas a very long shot usually has a long duration on screen. But we can determine if there is a correlation between any of the variables - camera movement and shot length, or camera movement and shot scale, for example.

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