Why a Year Should Have 13 Months

Sometimes sunk costs entice us to stick with what we have because of the time and energy we’ve already invested. You know, like after you are on hold for 10 minutes, you don’t hang up because you focus on your sunk cost–that 10 minutes–rather than the cost of additional wait time.

Maybe sunk cost is the reason we don’t have a 13-month year.

Where are we going? To the value of a standardized yearly calendar.

The 13-Month Calendar

Think of how nice it would be if every month were 28 days long. With precisely four weeks, months would not only be the same length but days would fall on the same number. So the first Monday of the month would always be the 2nd, the first Tuesday the 3rd, and the fourth Saturday the 28th. And yes, every month there would be a Friday the 13th.

In 1902, a gentleman who worked on statistics for the British Railway developed the concept of a standardized month. Enticed by the consistency the 13-month calendar created, Moses B. Cotsworth explained that all months retained their names while the extra month Sol (summer solstice) would be inserted between June and July. Unattached, the additional day he needed to get to 365 was placed at the end of December. The last detail, a leap year, meant that every four years, a 29th day preceded Sol 1.

The 13-Month Calendar:

From: citylab.com

When Cotsworth toured the U.S., the one famous person he convinced was George Eastman (Kodak camera inventor). Adopting the schedule for Eastman Kodak in 1924, Eastman had the year divided into 13 periods that served as a consistent organizational and financial planning structure. You can see the plusses. With equal months, resources could be allocated according to one monthly template. Comparing monthly sales, 28 days was the constant.

Although Eastman could not convince the U.S. Congress to switch to his calendar, Kodak used the 13-period calendar from 1924 to 1989:

From: citylab.com

Our Bottom Line: Externalities

Whether looking at time zones, weights and measures or the atomic clock, we can say that standardization creates efficiency. As a positive externality, that efficiency creates a slew of business benefits. Comparing monthly revenue for example, you always mean 28 days.

At home and for government, a standardized month would also come in handy. Told you had March 11 as a vacation day, you would know it was a Wednesday.

But yes, the sunk cost of the past precludes any possibility that we will ever switch.