# How to reduce Data Hoarding, get Better Visualizations and Decisions

Creating a hodge-podge of pretty pictures of every datapoint is a guaranteed way to destroy the value of a visualization. We examine how to reduce such data hoarding and improve decisions.

Perfect, **see how Variable Z is flat** and how the other variables were all spread out? Well that “spread” is variability. Our goal is to identify those “flat” planes, isolate them into **“non variable” columns and throw them out**, to simplify our analysis!

With that in mind, if we had to eliminate a column, we’d eliminate Z. Why? Because **almost every value is 40**.** There’s incredibly little variability in it.**

**I’m lost… What’s variability? Home Buying Example**

Let’s say you’re looking to buy a house and you’re a data-hoarder like myself so you build a spreadsheet. After narrowing down, we get to the last contenders:

So what columns can we eliminate to simplify our decision? Well… since there’s no variability in the blue columns– ** Neighborhood and Beds**— we can throw them out.

**WHY?!**Because Neighborhood/ beds won’t be the

**that we use to decide between houses.**

*“difference”*Notice how **Size Sq Ft** and **Baths** move together. In other words, for every additional bath, you get another 1,000 sq feet *(humor me)*. Therefore, if we can combine those into a new column called **Size**— we’re not losing any info, we’re just asking the underlying question–** “What size home do I want?”**

Finally, we can drop *“Realtor is creepy”* and* “Smells like wet dog”*— because those don’t stay with the house.

**Now we can weight our options by the decision drivers.** That’s the goal of the wonderful world of data and decision science!

Now, let’s look at dataset U, V, and W. (Note- there’s no “nearly constant” column)

**Let’s visualize!**

Well darn, looks super “variable” to me…

Hang on! **Let’s rotate our data** (something we discussed in **Causation vs Correlation: Visualization, Statistics, and Intuition!**) to see if there’s a better perspective of U, V, W.

**Still a blob… One more try!**

Got it! **See how from this perspective that U, V, W appears to be a disc? That’s what we’re looking for!** Let’s isolate that flat plane into a single column.

Sounds great. How do we do that?