Comparison of movie-production rates in planned and market economies
David J. Krus
Arizona State University
Analysis of trends can be of substantial value for research in social sciences. Compared to economics and business, the relative paucity of attempts to superimpose a secular trend line on obtained longitudinal data in social sciences is surprising, given the obvious advantages offered by suppression of random variation for highlighting the underlying regularities in the data. The elementary form of trend analysis is the moving average.
For a given data set, the shape of a moving average is specified uniquely by the choice of an order (the number of successive points used in computing each average) and a set of weights. In general, the greater the order and the more homogeneous the weights, the smoother the resulting moving average. If there is a clear trend in the data, a moving average of a reasonable order will mimic it. In cases of highly irregular data, a moving average may help to isolate the trend, if present. Judicious weighting, together with selection of a reasonable order, will minimize the chance of generation of trends not actually present in the original data.
An example of the application of the moving average to real data will serve to highlight the effects of the method. The data analyzed were collected by a count of movies In the 1910 -1970 time interval, produced in that part of the Austrian Empire which was later annexed by the Czechoslovak Republic. This count was based on the authoritative account of film history in that part of Europe by Skvorecky (1971).
Figure 1. Annual number or movies produced in Czechoslovakia, 1910-1970.
The raw data plot (broken line) includes a considerable amount of incidental variation, hard to explain, especially for the 1920 - 1930 period. However, the moving average (solid line) of the 5th order with weights 1,2,3,2,1, allowed for interpretation of the data in terms of secular societal events.
As can be observed, the increased movie production preceded both World Wars (1914 -1918 and 1939 -1945). The transition from capitalist to socialist economy in 1948 is reflected in decreased movie production, likewise, a decrement occurred after the invasion of Czechoslovakia by the armies of the Warsaw pact in 1968. However, the most interesting finding is the comparison of the highly irregular pattern of movie production during the capitalist economic system (1910 -1948) and steady increase in movie production during the socialist economy (1948 - 1968).
REFERENCES
Skvorecky, J. All the bright young men and women: A personal history of the Czech cinema. Toronto: Peter Martin Associates. 1971.