there are six categories of North Star Metrics:

Revenue (e.g. ARR, GMV):
The amount of money being generated — the focus of ~50% of companies.
Customer growth (e.g. paid users, marketshare):
The number of users who are paying — the focus of ~35% of companies.
Consumption growth (e.g. messages sent, nights booked):
The intensity of usage of your product, beyond simply visiting your site — the focus of ~30% of companies.
Engagement growth (e.g. MAU, DAU)
The number of users who are simply active in your product — the focus of ~30% of companies.
Growth efficiency (e.g. LTV/CAC, margins)
The efficiency at which you spend vs. make money — the focus of ~10% of companies. 
User experience (e.g. NPS)
The measure of how enjoyable and easy to use customers find the product experience, overall — the focus of ~10% of companies.

refining your ideal North Star Metric (NSM) — deciding which of the six categories above to focus on — depends heavily on your business model, how your product grows, and how your product is used.

Type of company: Marketplaces and platforms
Most common North Star Metric: Consumption growth

Type of company: Paid-growth driven businesses
Most common North Star Metric: Growth efficiency

Type of company: Freemium team-based B2B products
Most common North Star Metric: Engagement and/or customer growth

Type of company: UGC subscription-based products
Most common North Star Metric: Consumption

Consumption is more likely to result in users sharing the content, thus driving the growth flywheel

Type of company: Ad-driven businesses
Most common North Star Metric: Engagement

Type of company: Consumer subscription products
Most common North Star Metric: Engagement or customer growth

Spotify, which has both a subscription business (music) and an ad-based business (podcasts), focuses on engagement, customer growth, and consumption

Shopify, for example, focuses on growing customers (i.e. “active merchants”) rather than on consumption (the number of transactions). This is because rather than solely collecting a take-rate, the company also charges a subscription fee.

The difference, I suspect, is rooted in the recognition that inactive paid users will soon churn. Thus, there’s more power in tracking high-value paid users.

An alternative approach to choosing your North Star Metric is to ask yourself: What jobs are our users hiring our product to do?

the North Star Metric needs to measure what matters most when fulfilling the job to be done for the customer or user

Focusing on revenue goals too early can lead to suboptimal decisions, such as spending too much time optimizing pricing — or being afraid to lower pricing, for that matter — which can hurt your long-term business growth.

A goal around revenue can be uninspiring to the team. People often join companies to accomplish a specific mission;

Of course, in the end everyone cares about revenue, but there are some good reasons to avoid making revenue growth your singular North Star Metric.

Companies that do have multiple North Star Metrics typically only do so when they layer on a metric for quality (e.g. Superhuman, Slack, Duolingo), or when they have multiple products with different goals, like Spotify does with subscription music and paid podcasts, looking at both customers, engagement, and consumption.

To nail your output metrics, calibrate the input metrics

Once you have your North Star Metric (an output), your next step is to break this metric down into its component parts and decide which metrics (the inputs) to invest in.

With such granular and actionable input metrics, you can actually come up with concrete ideas and align teams around them as goals

Whenever you have a candidate for your North Star Metric(s), determine what levers move this metric, and then focus your ideation around those input metrics.

In the earliest stages of a company, however, before you’ve found the fabled product-market-fit, your singular aim should be answering one question: “Am I building something people want?”