A hypothesis about the performance-gain delivered by supervised topic models over unsupervised topic models for historical archives as corpus, pertaining to secular versus non-secular changes in the response variable

The article "Money, Prices and Wages in the Confederacy, 1861-65" by Eugene Lerner (Lerner 1955) initiated a debate in which Lerner described the increasing inflation in the Confederacy over the course of the Civil War, and analyzed its reasons, attributing it to the increase in the stock of paper money over the duration of the war. This stock kept rising (Lerner 1955, p. 20, Table 1) because of several factors: Firstly, owing to the war, factories were not only being destroyed in the South, but also, due to the disruption of supply routes, those factories that still functioned were being starved of their raw materials; as a result of both of these factors, money that otherwise would have been invested into production could not be so invested, and hence remained in circulation, increasing the circulating money stock over time. Secondly, to fund the war effort, the Confederacy also kept minting new money, which further swelled the existing stock of money in circulation. Lerner also gives an estimation of what the month-bymonth consumer price index (computed overall, that is, for the entire Confederacy) had been for the duration of the Civil War, computing the equivalent of a consumer price index series based on the quotations for each of a carefully selected mix of common commodities, such that each commodity in the mix had been continuously listed in the newspapers during the Civil War’s duration (Lerner 1955, p. 24, Figure 1 and Table 2). Because inflation was constant and uninterrupted, the CPI values in the series kept increasing throughout the war.