It’s a common criticism of America that the way we format dates is illogical. It’s so common that I now roll my eyes when I see images like this on Facebook:
If you are unaware of the criticism, the month, day, year format (M-D-Y) can be rephrased as, “Medium size unit, small size unit, large size unit.” Those outside of the US typically format dates as D-M-Y or Y-M-D, because it follows the logical progression of the sizes of the units. Days are smaller than months which are smaller than years! Our forefathers (or whoever established the M-D-Y format) must have been idiots! However, I would bet that most people can’t really argue as to why size of the unit is the best way to order the format. To provide some support for why the M-D-Y format makes sense, I offer the argument that the American format orders the units by importance of the information the unit conveys, in common usage.
How often do you write a date without the year? If you are telling someone a deadline next month, you may write it as, “Send me the file by 10/15 (October 15th).” The year is often meaningless. People can assume by context that you are talking about the current year. Similarly, people often write dates without the day of the month. “Yes, we’re getting married in 10/15 (October of 2015).” Again, the context tells the listener that they are giving a general time, and the day of the month doesn’t matter. Now, how many times have you seen a date without the month, such as “I’m moving on the 10th of the month in 2015?” The only instance I can think of is when giving a single unit of time (e.g. “Get it back to me by the 15th” or “We’re getting married in 2015”). However, in these cases formatting doesn’t really matter since there is only one format. The logical conclusion is that across the several formats of dates, it makes sense to always put the month first, since it is the only constant piece of information.
The units also carry different amounts of information. For instance, if you remove yourself from a specific time, days of the month carry virtually no information. Saying “the 15th of the month” is virtually meaningless outside of where that is relative to the current date (e.g. “that’s 2 weeks from now”). The 1st of the month is associated with rent payments, etc., but I would argue that such information is used infrequently. Months, however, include information about the seasons and other activities that recur yearly. If you are in school, August or September are probably associated with going back to school. December is associated with holidays. When you are thinking about celebrating someone’s birthday, the month generally carries the most important information. Sure day of the month is necessary, and the year tells you their age, but the month helps you determine how far away it is, when to start planning, who else to group the birthday with (e.g. if you have a single office birthday party once a month), etc.
I, of course, am not saying MM-DD-YYYY is the best format. Instead, as Howard Moskowitz may say, “There is no best format — only best formats.” When dealing with recurring events, the month is often the most important piece of information, and learning that information first makes sense. However, the year is often very important, so the international standard of Y-M-D makes the most sense in many cases (especially on computers where it is the easiest to sort by date). Really, though, I’m not even advocating for M-D-Y’s normativity. Instead, I argue that when people don’t understand why something is the way it is (especially if that thing differs from what you expect), it is better to put some thought into figuring it out then to assume everyone is dumb.