Mathematics, Excel, and Personal Decision Making

In the late 1990s I attended a career planning class. Part of the class included a method of handling large decisions (e.g., career choices, places to live, etc.). While the course walked us through the process on paper, when I got home, I started using the approach in Microsoft Excel, probably because my handwriting is messy. Today I’ll be sharing that decision-making process–as I remember it–mostly as a way to help you apply some data to difficult choices. I found that I needed this in my 20s because at the time I made a lot of decisions based entirely on my feelings. Maybe you’ll find it useful, too.

The Process

The short version of this thinking process is:

  1. List the key attributes of each choice.
  2. Rate each alternative on a (subjective) scale of 1-10.
  3. Rate them against each other to determine what your priorities are.
  4. Score your results.

List the Key Attributes

Ideally, you want to be able to rate your choices on a consistent basis. For a home, those attributes would likely include price, size, and proximity to work, schools, stores, healthcare, etc. For a car, your attributes might include price, mileage (if you’re buying used), accessories, and color. A new job could include items such as work content, pay, location, company size, and company culture.

Rate Each Alternative

Some attributes will be pretty straightforward, such as price, because they’re already a numerical value. Others, such as the “feel” of a new neighborhood or the corporate culture at a new job will have to be purely subjective. Even so, you want to apply a consistent, albeit subjective scale of 1 to 10 (10 being highest).

Rate Them Against Each Other

In this part of the activity, you rate each attribute of your choices against each other by importance. Which is more important to you in a home: price or location? Price or size? Price or access to entertainment? Go down the list. Then start with the second item you wrote down and repeat the process. Which is more important to you: location or size? location or access to entertainment? Et cetera. You run through all of your alternatives until you know how each of them would fare against the other, then you count up which alternatives “won” the most decisions.

Score Your Results

Okay, so now you’ve got your list of attributes in priority order and you’ve got your options rated. Your table might look something like this:

You can already see some patterns here. On your first priority, price, Option A is the clear winner. However, Option C is the clear winner in four other categories. If you want to get mathematical, though, you can add one more number to your findings, which is the average of all each option’s attributes. Starting with Option A, place your cursor in cell C9, which is the cell (box) below all your scored alternatives. Speaking in computerish, you type:

=AVERAGE(C3:C8)

Then type Enter or Return.

This is telling Excel to calculate the average of all the numbers in that column. It should look like this:

To save yourself some time, you can copy this formula (Ctrl-C or Command-C depending on whether you’re using PC or Mac) and paste it (Ctrl-V or Command-V) below the other two columns. Your results will look like this:

So now you’ve got an average of your options. And while Option A might seem to meet your #1 criterium, it doesn’t fare so well overall. In fact, Option C, while the worst on price and proximity to work, had the highest overall score. If the scores are close, you can also count how many times each option scored highest in each attribute.

You can play with the numbers more, if they don’t quite meet your expectation–though that spoils the point of having numerical scoring. (If you’re a math wiz you could add more “weight” to your higher-ranked attributes…I don’t know how to do that, however.)

I hope you find this tool useful. I’ve used it for high-cost, high-impact items such as relocating, job choice, car buying, and vacation selection. At the very least, it can help you rein in your desire to lead entirely with your heart. Your numbers might match what your emotions are telling you that you want anyhow, but it’s nice to have some sort of confirmation.

Why yes, I am a geek, what do you ask?

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About Bart Leahy

Freelance Technical Writer, Science Cheerleader Event & Membership Director, and an all-around nice guy. Here to help.
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