Tuesday, December 16, 2008

Prioritizing features

So we've built our list of (it turns out) over 85 new scope features that the site should someday have (through "pie"-in-the-sky brainstorming). How do you prioritize 85 new features? Which ones should we concentrate our efforts on - which are more or less important than others. Basically this can be done with a "factorial decision tree". Let's take a more manageable example. Say I know I like 5 pies, but can't decide which one to eat. My list initially looks like this:

PiePriority
Cherry Pie
Peach Pie
Pecan Pie
Blueberry Pie
Apple Pie

So the next stage is to take our first table item and compare it to each other item below it in the list. If we HAD TO CHOOSE and we could include only ONE of the two items in the final product (or in this case to eat) which would we choose. If we chose the first item we flag that one, and if we like the second item we flag that one instead. So for our first comparison we compare Cherry to Peach Pie. If I had each in front of me and had to choose one, I'd choose Peach. I'd score a 1 for peach and not points for cherry. Our next comparison is Cherry to Pecan. I'd prefer Cherry, so I score one for cherry, and none for Pecan. My next choice is Cherry and Blueberry, etc. till I reach the end of the list. So after round one we should have as many hash marks as (# of items - 1):

PiePriority
Cherry Pie1 1
Peach Pie1
Pecan Pie
Blueberry Pie
Apple Pie1

After round one is done we go to the second item on the list and compare to everything under that. Peach to pecan, Peach to Blueberry, etc.:

PiePriority
Cherry Pie1 1
Peach Pie1 1 1
Pecan Pie
Blueberry Pie
Apple Pie1 1

You continue to work your way down the list until you've done all the comparison. Here is my final result:



PiePriority
Cherry Pie1 1
Peach Pie1 1 1
Pecan Pie1
Blueberry Pie
Apple Pie1 1 1 1

We then translate the priority hash marks into numbers that are the final weighting of each item:


PiePriority
Cherry Pie2
Peach Pie3
Pecan Pie1
Blueberry Pie0
Apple Pie4

The final weighted and rated rankings end up as: Apple, Peach, Cherry, Pecan, and Blueberry. If we wanted we could do a run off with matching choices if we had lots of choices by using the same methodology to choose one over the other and scoring it. And now you know I like Apple pie.... :)


The last step will be to add scope and complexity measurements to the lists. That we'll reserve for next post.

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