Formatting your spreadsheets well makes your data easy to read and analyze. But you can also format your data so that its appearance changes depending on what the data is. This is called “conditional formatting.” It is really useful. For example, imagine you have a long list of student grades. You can use conditional formatting to highlight those students who are missing an assignment. You can try out conditional formatting in the Format menu. It’s easy to use, and makes a big difference in spotting important data quickly. 

Not all data is created equal. There’s an old saying: “garbage in, garbage out:” if your data is bad, your results will be bad as well. Problems in data come in many forms. First, data can just be wrong. I’m not talking about deliberately fabricated or misleading data (that’s a whole conversation in itself!). It is easy to make typos or have errors in importing data from other sources. It’s good to always do a “reality check” on your data. If you’re looking at grades that should be between 0 and 100, do you have any 1200s? If your carefully-computed list of car efficiencies averages 30 miles per gallon, is that one car at 100 mpg an outlier? You can catch a lot of problems just by quickly scanning over your data. 

Another kind of error can happen when a function does something you don’t anticipate. For example, the SPLIT() function divides text based on a specific character. It can be used to split “Amanda Fish” into cells for “Amanda” and “Fish”. I frequently use this formula when I get a new class list, to get first and last names. This works great most of the time, until you have a “John Von Neumann.” Now you have THREE columns of names, and the rest of your spreadsheet is thrown off. 

Always check over your raw data and your computed data for any potential problems. It can save you from extra work or embarrassment later.