Product Market Fit
How do you know if you have PMF? Fred Wilson of Union Square Ventures describes it as "getting to the point where the market accepts your product and wants more of it".
To quantifiably measure this, most companies will use a combination of the metrics below:
1) PMF Survey by Sean Ellis. This survey measures a user's level of dependency on a product. Ask your users "How would you feel if you could no longer use [your product]?". If 40% of users answer that they would be “very disappointed”, you have PMF. For examples of how to conduct this survey, read Slack PMF Survey by Hiten Shah and How Superhuman Built an Engine to Find Product/Market Fit by Rahul Vohra
2) Net Promoter Score Survey. According to Rahul Vohra from Superhuman, "this survey measures how strong your word of mouth is [and] how viral your product can be in the real world". The NPS survey asks "On a scale of 1 to 10, how likely are you to recommend this product or service to a friend or colleague?". Those who answer 0-6 are your detractors, 7-8 are passives, 9-10 are your promoters. Your NPS = % promoters - % detractors. According to Hiten Shah, the best companies aim to a NPS of 70+ (Tesla has 96 and Apple has 72).
An important note on NPS pointed out by [Rahul Vohra](https://www.drift.com/blog/how-to-measure-product-market-fit/) is that NPS is driven by non-product things including "how great your customer support is, how great your brand is, how smart you make your users look or how cool you make them feel".
3) Flattening Retention Curve by Brian Balfour. A retention curve measures how many users your product retains over a period of time. If the retention curve flattens, it means you have a group of users that are continuing to stick around using your product - you have found PMF with this set of users. The next step is to understand the difference between the user segments and create experiments to increase the number of users retained.
Source: Product Market Fit by Brian Balfour
4) Engagement Metric. An engagement metric measures the amount of value being delivered to a user. The metric varies according to your product or service and the key is to pick a metric that indicates core product value is being repeatedly delivered.
A few example metrics provided by [Brian Balfour](https://brianbalfour.com/essays/product-market-fit) are
"For a photo sharing app, that might be the number of photos users are sharing on a daily or weekly basis. For a messaging app, that might be how many unique people users are messaging per day. For a B2B SaaS app that helps you with invoicing, the engagement data might be around how many invoices processed per company."
An important note on engagement metrics is that the engagement metric alone is not enough to indicate PMF - it must be paired with other measures. A great example pointed out by Casey Winters of Greylock is the case study of Homejoy's failure where home cleaning bookings were skyrocketing while customer retention and unit economics were ignored.
Dogfooding
Dogfooding is the act of using your own product everyday. It's the easiest and quickest way to validate that your product solves your own problems.
Iteration
An iteration is a minimal working state. The intention behind iteration is to quickly and continuosly deliver incremental product value.
Breadth and Depth
Driving the right balance between going wide to solve more problems our users face versus going deep to increase usage and revenue.
Companies Without Product Managers
For the first 5 years, up until 2015, Stripe did not have any formal product managers. The reasoning behind this was (1) Their engineers were users of their own product (2) Product was led by engineers who had experience going from 0 to 1 (i.e. ex-founders) (3) Iterations happen quicker in a single person's head where they are able to design and implement. - Does Stripe Have Product Managers Or Do Engineers Manage The Products Themselves? by Patrick Collison
Some other companies who don't have product managers include: Behance, Basecamp - Twitter Thead by Suhail