Patent activity in the Polish food system and the business cycle. Conclusions from spectral analysis

Invention activity is an important innovation development factor, as it not only imposes changes in economic activity, but also often leads to the completely new structures within sectors. The aim of the paper was to investigate the relationship between macroeconomic and sectorial business cycle, and the patent filings in the food system in Poland in the period 2006–2022 taking advantage of statistics defined in time and frequency domains. Data on patent applications from 34 IPC classification (sub-)classes were analyzed, combined into five groups: food, beverages, tobacco, agricultural chemistry, agricultural machinery and packaging. The results obtained with spectral and cross-spectral analysis tools were compared with results obtained in the time domain. The positive relationship between patents and macroeconomic cycle is the strongest for cycles lasting 3.5–4 years, which dominate in reference to GDP series in the analyzed period. Patent filings are strongly positively correlated also with the agri-food sector output, especially in shorter cycles of 2.5–3 years. Although cycles of patent filings fluctuate much more than both business cycles, they seem to be more similar to the agri-food sector fluctuations. Moreover, patent activity may be treated as an early warning indicator of sectorial economic activity, whereas it’s lagging in reference to the aggregated economic activity.