Product Principles = Better Products

Shane Doyle
4 min readJul 3, 2016

When I first became Product Owner my mentor (who was also my manager) recommended that I read a book; “Inspired: How To Create Products Customers Love” by Marty Cagan. She said that the book had helped her in becoming better at creating products. She was a fantastic mentor and an even better Product Manager. So needless to say I got the book.

The book is a fantastic book and wonderfully written. If you’re a product person or are interested in creating wonderful products then I highly recommend it. However this article is not a review of this book so why am I writing about it? Well, in chapter 13 of this book Marty writes about Product Principles or “Deciding What’s Important” and that’s what I’m going to write about here. How this book and especially that chapter has helped me in understanding what’s important when creating products.

So what exactly are Product Principles?

Product Principles are a set of beliefs and intentions that reflect your team’s values and vision. These can be used in providing direction to the team and in understanding what is deemed important to the team (and the product). Also, it can serve as a base for inspiring product features.

These principles are then declared in a Product Manifesto which is just a document that contains a prioritised list of the principles. The Manifesto is neither a list of features or is tied to a certain version of the product but the product as a whole. A benefit for having a Product Manifesto is that it can bring the product team (and other teams) together and keeps everyone focussed on what’s important.

Let’s go through some gotchas:

  1. These principles are not design principles, a design principle could be “Hierarchy: helps the user navigate your design” and this is not a product principle. A product principle could be “Community: we believe that community is the most important part of our product”.
  2. Try not to be vague or generic when creating principles. This will make them useless. So don’t say “Must be reliable”, of course, it must be reliable who want’s to create a product that’s not reliable.
  3. When creating a set of product principles make sure to include the whole product team. This is not a product manager only task. The whole team should be involved in coming up with them and prioritising them.
  4. Don’t go over ten in the number of product principles you’ve set for your product. Anything in position 10 or lower is really not a priority. Personally, I would try to keep it below 8.

So how will it help me build better products?

Firstly, all your product principles should help provide direction and guidance to the whole of the product team. This should enable the team to focus on developing inspiring product features that are important to your product.

Secondly, it should help reduce conflicts (disagreements, spats, or whatever you want to call it) when developing new product features. Imagine the following scenario; you’re developing a new feature for an app that allows people to buy and sell bikes. The feature we’re developing is going to make it easier for your users to sell their bike by only asking users for a photo, price and name of the bike. But there’s a problem, half of the team thinks that this is an amazing feature but the other half think that it will make it more difficult for buyers to find a bike. So you spend most of the time debating which is right and which is wrong, whatever decision you make half the team will be disappointed. This is not an uncommon scenario in product development and this can be relieved by having a set of prioritised principles. If you’ve previously set in your product manifest that the most important principle is that users should be able to sell their bike as quickly as possible then the argument is over.

If none of the above are good enough reasons as to how it will make you build better products then I’ve clearly written this article badly and wasted two or three minutes of your time. 😜 (that’s my way of saying sorry)

If you’re looking for an example of a product manifesto then I recommend the following link:

Did you like this article? If so, tap the ❤️ below.

And finally, learn more about my work @



Shane Doyle

Husband • Dad • Lead Product Designer • 🇮🇪🇪🇺 • • co-founder of