Kano Model for Prioritizing User Stories/Requirements

Regardless of whether you subscribe to Waterfall or Agile as your preferred methodology, some form or prioritization of requirements (Waterfall) or user stories (Agile) will take place.

One of the more difficult tasks is helping the user community to determine the varying degrees of importance of each requirement. One method to help with this process is the Kano Model.

The Kano Model is named after Professor Noriako Kano who in 1987 developed a theory for product development to classify features into five categories based on answers to questions about the specific features. Following are the five classifications.

Attractive	Delighted to have but unexpected.
One-Dimensional	Features customers compare with your competition.
Must-Be	A must have feature.
Indifferent	Neutral about the feature.
Reverse	The customer do not want the feature and actually expect the reverse of it.
Questionable	Indicates that the customer is unclear about the nature of the feature

The features are classified by asking the customer two questions – one functional and the other dysfunctional – to which the customer selects one of 5 possible answers.

The questions are:

1. How would you feel if the feature was present in the product?
2. How would you feel if the feature was absent from the product?

The answers from which they may choose are:

1. I would like that.
2. I require that.
3. I don’t care about that.
4. I can live with that.
5. I dislike that.

The initial reaction of most people when posed with the functional/dysfunctional question think “won’t the questions offset each other?” As it turns out most often they don’t.

An excellent example that I’ve heard in the past is with a milk carton that has a thermometer on the outside so the customer can see what temperature the milk is. One may select answer 1 I would like that as the functional answer but select answer 4 I can live with that for the dysfunctional question.

The answers are then compared to a matrix below to arrive at the classification. The letters in the middle of the matrix represent each of the classifications via its first letter, e.g. A=Attractive. To take our earlier example of the thermometer on the milk carton, the functional was Like and the Dysfunctional was Live With thus the matrix indicates that the classification is A=Attractive.

	Dysfunctional
		Like	Expect	Neutral	Live With	Dislike
Functional	Like	Q	A	A	A	O
	Expect	R	I	I	I	M
	Neutral	R	I	I	I	M
	Live With	R	I	I	I	M
	Dislike	R	R	R	R	Q

With the Kano Model, one is able to ask the customer two short and concise questions and ultimately gather critical data regarding the importance of the feature to the product. As a result, a development team can easily discern what’s mandatory, what’s nice to have, and where the land-mines are.

There are additional techniques that can be used in combination with the Kano Model to further prioritize requirements like weighting features but alas that will have to weight for another day.