Every few months I cook for a group of friends. I like to cook, but my dinners are more a series of ill-timed surprises than cohesive meals. I serve food at random intervals. A main dish may be served in 20 minutes; salad, 30 minutes later; bread, after everyone finishes eating; side dishes, abandoned in the oven for hours, never make an appearance. However, with enough wine, everything generally works out in the end.

At any time during my dinner, an experienced cook could point out what needs fixing: a pinch of salt here, turn the heat up there, put out the fire in the oven, and so on. This type of review is a heuristic: an analysis and grading of individual parts. You can apply a heuristic to nearly anything, from the preparation of a meal to the user experience of software.

Some meals are better than others. Rather than say, “This dinner is terrible,” a dispassionate reviewer might give it a passing or failing grade, “Dinner: Fail.” Likewise, rather than say, “The chicken paprikash tastes like burnt Saran Wrap,” it would be more precise to rate it as “Main Dish: Severity 5.”

Applications, especially large ones, can be overwhelming to analyze in their entirety. However, large or small, applications are made of parts. We can evaluate each part and determine if it is acceptable, like a food critic evaluating each of a meal’s courses.

Heuristic scoring uses pass/fail grades, 0–5 ranges, and 0–100 percentages, or any combination of numeric or Boolean values.

Of note: a heuristic’s average is the sum of all scores divided by the number of scores. (5 + 2 + 4) / 3 scores = 3.6

In 1990, noted ¹usability experts Jakob Nielsen and Rolf Molich created a robust set of usability heuristics that are still in use today. The Nielsen heuristics cover everything from aesthetics to error prevention. Read more about “10 Usability Heuristics for User Interface Design” at https://goo.gl/zoQKAN . Researchers use several other frameworks, as well, such as Gerhardt-Powals and Weinschenk and Barker.

Once you apply a heuristic across your application, you indicate what works and what does not—what needs your attention and what can wait. Perhaps you will choose to tackle parts graded from three to five, or fix everything marked as a “fail.”

Evaluate each part, make improvements, and your guests will return for second helpings.