I built a dataset of all original patent applications that have been published January - August 2009. Using that dataset, I created the chart below showing the patent applications grouped by the day of the week that the application was filed (based on filing date listed in publication). As is apparent, Friday filings are the most prevalent while only 2% of applications were filed on the weekends. As shown in the second and third charts, the Friday filed applications on average (1) include more claims and (2) include more words in the detailed description as compared to applications filed on other days of the week. Applications filed on the weekend are significantly shorter - a phenomenon likely explained by the larger proportion of independent inventor filings on the weekend.
