Archive for August, 2014

August 15, 2014

No, Virginia, Null is NOT An Answer

Okay – null sounds an awful lot like “dull” – but stick with me for a minute here: understanding null now will help you later when you really need to run that report!

If you haven’t run into the null problem yet, you probably will. It goes like this:

Chief Marketing Officer: “Can you get me a list of everyone that bought a widget last month and likes to drink beer?”

You: “Sure – we have all of that data in our database, because you had me add “do you like beer?” to our credit card checkout form!”

So you run the report and hand it over and your CMO wants to know why no one likes beer! And it turns out that you have a NULL problem! It’s about blanks. And we know how blanks turn out:

  • “He had a blank stare”
  • “My screen suddenly went blank”
  • “The signature on my check was blank, so I was charged a late fee”

You’ll most often see a null value when you haven’t required someone to give you an answer. In the case above, you probably didn’t make the “do you like to drink beer?” question required – so some people said yes, some said no, and most left it blank.

It’s worse when there really *ought* to be an answer. Try this one – gender. Everyone has a gender identity – so if you ask that question and don’t make it mandatory – you’ll get blanks. Which leads to your CMO looking at you like you are crazy: “What do you MEAN we don’t know what Patrick’s gender is?!”

When we store data that is supposed to be binary (like a yes or a no question), we really have three states:

  1. Yes
  2. No
  3. We don’t know

It’s that last one that turns out null – and what it really means is that you didn’t ask the right question, or you didn’t ask it in the right way.

Here are some tips for avoiding getting to null:

Don’t add optional questions to any of your online forms or interactions. Besides being a poor user experience (what does my salary have to do with signing up for your newsletter?) it practically ensures that you’ll have null or blank values.

Don’t ask for information that you don’t need right now. Sure – your fundraising efforts get better when you know a lot about me. But don’t forget that we’re trading – you give me something I want, and I give you something you want. If we just started dating – you shouldn’t be asking for my salary.

Make sure your internal data entry practice is sound. That means looking at all of the spots where you are storing data, and figuring out a default value. So if you have a spot to track my gender identity – one of the options should be “not provided” – so you can tell your CMO that Patrick DOES have a gender – but doesn’t want us to know.

Regularly look for null or other confusing data points, and fix them. It happens – you import some data, switch tools, or otherwise end up with data that isn’t clear. That’s okay – just don’t let it clog things up. At regular intervals – run a report and look for null or blank values, and make a plan to clean them up.