We've all walked into a public restroom and had to make a choice of which stall to use. There are factors that sway our decision one way or another. Sometimes there is a mess that we would want to dodge  or a smell that we can't stand.  Aside from the obvious scenarios that we all would avoid, the next question we ask ourselves is, "which restroom stall is the cleanest?"

 You can bring your own sanitizer or wait until the janitorial staff does their round of cleaning, of course. Otherwise, an educated guess is your only bet to determine which restroom stall to use. Let's assume that the biggest determining factor of cleanliness would be frequency of use.  Research shows that given several relatively equal options, people will tend to choose the middle one. This goes for everything from which piece of cake to take to what shirt to put on your back. Psychologists call this the "Centrality Preference." Based on this logic, the most frequently used restroom stalls are likely to be the ones in the middle. 

Frankly, we all like privacy when we go to the bathroom. Being at home is probably the most comfortable situation for most of us, and some people will even go to such lengths as to only use their own private facility. In most cases, the first stall you pass in a public restroom is the least private. Based on this, the first stall is likely chosen least frequently by people and could be the cleanest. A small survey done in 2015, calculated that people generally look for the cleanest, largest, and most private stall when given a choice. Do you think the handicap stall is used less frequently because most people follow the rules? Think again. 

Beyond visual and olfactory inspection, there are two things to consider when determining how clean that stall truly is. First, have you ever walked out of the bathroom and seen that checklist on the restroom door with times and initials from the building staff? If it is up to date, you can probably assume that the facilities are well-maintained. If not, you'll have to draw your own conclusions.  Second, how full are the toilet paper dispensers? The restroom stall with the fullest dispenser will likely be the most recently cleaned or the least frequently used.  We all have our preferences when choosing what stall to use. If cleanliness is a priority to you, look for the signs of a recent visit from the janitor, and avoid the largest, most private, and more frequently used stalls.