Thursday, September 7, 2017

Missingness at the Museum

Pic credit By Ingfbruno - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=29455109


Explanation on the title: Missingness is the term for missing data. I may come across it more than
most people because I've read a lot of blogs on data scraping projects. It occurred to me that it really fits the context for this post.

The museum in question is the AMNH, which is world-famous for its dinosaur exhibits, though not so famous for its pricing structure. This is just one aspect of missingness in place.

The lines to purchase tickets get fairly long at this museum, though this past Sunday was not nearly as bad as another summer Sunday in which the line extended outside and around the block. Perhaps the special exhibit on mummies is not such a great draw. (BTW if you are interested in mummies or anything else Egyptian, you really have to take a trip to Brooklyn to see the exemplary collection of the vastly underrated Brooklyn Museum.)

I'll talk briefly about the problem with pricing information because it is related thematically to missingness, though it is not my main point. As I said, the lines to pay get very long despite the fact that there are various options to purchase tickets without waiting on that line. They include buying them online and buying them at the machines right next to the lines in front of the human cashiers.

On this particular trip, the family behind me on line made two attempts to purchase tickets via machine and then gave up and returned to the line. I noticed only one group that got off the line, purchased the tickets there, and then went straight in. Why is that? Wouldn't everyone want to cut out the wait time and go straight in?

There are a number of reasons why people persist in waiting for humans, but the primary one seems to be confusion. The entrance to the museum offers various ticket levels, from basic, to plus-one, to all-inclusive. Those prices themselves also vary by age and status: adult vs. student and child. But there are two additional factors that complicate the selection even more: One is that some of the "specials," which include both temporary exhibits and films call for times entry. The other is that really the basic admission price is supposed to be "pay what you wish" just like at the Met. However, any time you add on any special, the basic "suggested" price is rolled in.

 You may be willing to forego the specials to knock down your basic admission price from $23, but that's not an option you have when you pay at the machine. It will only accept full payments. It also will not issue you a ticket for showing your Bank of America card on the first weekend of the month. Yes, this museum is among the ones that participate in the Museums on Us program, but if you didn't check this out on your own, you'd have no way of knowing it from your visit in person. Consequently, it seems that people rarely take advantage of the program. In addition, due to the pricing structure in place, the museum does not allow visitors to count the Museums on Us entry as covering the basic cost and allow for an add-on price just for specials, something other museums do allow.

Given the fact that most of the people in the line appeared prepared to pay full suggested amounts, though, it becomes clear to me that they either don't realize that the machines will help them complete their transactions faster or that they want the person to provide information and guidance on the profusion of alternatives available. This is a major flaw in informing the public about how thing work there ahead of time in order to expedite entry.

Now to the main point of missingness, which some people fail to grasp altogether: the missingness in basic numbers that are accepted as the basis of data.

On this trip, we took a guided tour of museum highlights (though we've seen them all before). This guide included a stop in the Hall of Ocean Life, pointed out the blue whale (which you really can't miss) and spoke about how scientists come up with the population numbers now versus what they were in the past. He explained that in the past, when whales were hunted, the numbers were a function of the number killed with an extrapolation for how many must still be out there. Now that hunting whales is illegal, they use other methods to come up with an estimate of the numbers, and so they conclude that the population has diminished.

Now, I recall years ago reading about people who used a similar method to justify catching and killing wild mustangs. They figured that there were several that they didn't see for each one they did. At the time, that approach came under fire from those who considered it to favor the hunters by allowing them overstate the numbers. So if the same was the case for whales, the numbers estimated in the past were likely overstated. Even if there were not, comparing that system of counting with a count that is based on completely different assumption of counting is the proverbial comparison of apples to oranges. In other words, you're mixing two completely different systems with their own sets of missingness to come up with conclusions about numbers, and that is both inconsistent and misleading.


There is a great deal of guesswork in science. Certainly, the guide admitted this in showing the Titanosaur. Not only is it not the actual fossil but a 3D printed replica, but the replica head is based off of a completely different fossil because no head was present. We see things put together as one and assume that they are accurate. But that is often not the case, so we have to bear in mind that even visualizations that appear compelling may not reveal the whole story of the data. Misssingness  can be dealt with, but one has to know which approach was taken and whether that solution contributes to better understanding or pushes to a particular outcome that is not truly objective. For true scientists, getting things to fit alone is not the answer. That's why you see reworkings of dinosaurs exhibits every once in a while. 

Related: http://writewaypro.blogspot.com/2016/10/data-visualization-you-have-to-c-it-to.html