market sizing case jobs to be done

Understanding the size of a market is a critical step to determining how much to invest in developing a new product for that market, or if it's worth investing anything at all. This article shows you how to use Jobs Theory and your customer's job-to-be-done to size a market as opposed to a product-based market definition. We'll also give a few of the best market sizing questions to ask, and discuss the two key benefits of job-based market sizing:

  1. A more accurate estimation of your market opportunity
  2. Avoiding the trap of incrementally improving a product while missing innovations that disrupt your business

Job-Based Market Sizing

Perhaps the most popular method for sizing a market is to multiply the price of the product by the number of units sold. The most commonly used product-based market sizing formula is

Market Size = Product Price * Number of Customers

What do you do if you haven't developed your product yet and don't have any customers for which you can calculate the lifetime value? How do you determine the total addressable market (TAM) for new opportunities?

To size a market opportunity, instead of analyzing the products currently in the market, define the market from your customer's point of view: a job beneficiary plus their job-to-be-done. (A detailed explanation of this definition follows below.)

Determine the value of the market by asking customers what they are willing to pay to get the job done and plot the answers on a curve from high to low. We call this graph the need curve. The area under the need curve is the size of the market, known as the market size.

estimating the market size

Determining Willingness to Pay with Market Sizing Questions

While asking customers what they are willing to pay is straightforward enough, there are some other things to ask yourself as you begin sizing your market:

  1. Are your market sizing questions specific enough? Are you sizing the market in the city or the metropolitan area? What is the time frame you’re focused on -- weeks, months, years? Make sure you know what your goals are in asking the market sizing questions in the first place. 
  2. How are you asking the market sizing questions? Are you surveying them directly? Are you doing an indirect survey where you give them options and ask them which one they’re most willing to pay for? Are the surveys done online or in-person? The approach is important. Positioning the questions as part of a customer satisfaction survey will usually lead to better answers because customers are always happy to give feedback about how they can be better served.
  3. Are the questions open-ended enough to give you good data? Are you asking leading questions, or keeping them unbiased?

Market Sizing Questions to Ask

Customers are not buying your product. They are hiring your product to get a job done. Traditional market definitions are flawed because they all use the product as a key variable. Here are some good market sizing questions to ask both yourself and your customer to get accurate data about willingness-to-pay to get the job done:

  • Who is the job beneficiary? In other words, who is benefiting from getting the job done?
  • What is the customer’s functional job? What goals are they trying to achieve in either their personal or professional lives? How quickly and accurately can your product help them achieve that goal?
  • What is your customer’s emotional job? How do your customers want to be perceived by others while executing their functional job? How do they want to feel about themselves while executing their job?
  • What is your customer’s consumption job? What do they need to do to utilize your solution? Do they need to learn something? Install something? Maintain or repair it themselves? How willing are they to do these things?
  • To size your market based on your customer JTBD, ask customer at what price per month would a solution be:
    • so expensive that you would not consider it?
    • starting to get expensive so you would give it some thought?
    • a bargain -- great value for the money? 
    • priced so low that you would begin to doubt the quality?

These questions should give you more accurate data, as well as a better idea about what types of jobs your customers are hiring you for. Knowing this information, you can then decide which pricing strategies to use.

How Product-Based Market Sizing Fails

Sizing opportunities with a product-based definition of the market is like looking in the rearview mirror and can lead to lethal mistakes.

For example, a team at Microsoft likely used traditional methods to calculate the size of the "iPod" market at its peak. Apple had sold 200 million iPods at $150. Using traditional methods, this logically appears to be a $30 billion market (market size = price of the product x number of buyers). Microsoft launched the Zune into the "iPod" market, and it failed consulting market sizing questions

Jobs Theory reveals the lethal flaw in this traditional market sizing method: consumers don't want iPods any more than they want records, cassettes, or CDs. They are not buying these products, they are hiring the products to get a job done. This is why the "iPod" market (like the "cassette" market and the "CD" market) is now rapidly approaching $0. New products have emerged (smart phones, streaming apps) that get the job done better for the customer. 

The Zune was doomed from the start because Microsoft defined the market incorrectly. They launched a product and used a platform that mirrored the iPod while others focused on the features and platform that would get the job done faster and more accurately. 

Traditional market definitions have led to large company failures throughout business history, including the downfalls of Blackberry, Britannica and Kodak. These companies failed because there are no "keyboard device," "encyclopedia," or "film" markets. These are all products that declined rapidly over time. On the other hand, there are, and always will be, markets to "execute jobs while mobile," to "find information," and to "share memories." These are all stable JTBDs.

Apple, Google, and Facebook created three of the largest market value companies in history by helping customers get these jobs done better.

The "cassette," "film," and "encyclopedia" markets were all once considered large markets, but they no longer exist in any meaningful way. Markets exist not because products are being sold to customers. They exist because customers are struggling to get a job done at a price they are willing to pay. This is a key insight from Jobs Theory: the struggle to get a job done is what causes a customer to look for a new solution. As a result, helping customers overcome this struggle is what causes a purchase and results in revenue and equity growth.

Constructing a Jobs-to-be-Done Market Definition

All of the traditional market definitions below are based on products. However, as we’ve seen, products are merely point-in-time solutions that help customers achieve a goal in their personal or professional lives (i.e. execute a job, job-to-be-done, or JTBD).

Total addressable market (TAM)

All units sold in a product category * price per unit

Serviceable addressable market (SAM)

Units sold of a specific product type * price per unit

Potential market

All customers with interest in a product offer

Qualified available market

All qualifying customers with interest in a product offer

Target market

The segment of the market a company pursues with its products

Penetrated market

The percentage of customers buying a company’s products


A job-to-be-done is a constant that is independent of products. This is true for business-to-consumer (B2C), business-to-business (B2B), and medical markets. For example, in order to execute the job of "creating a mood with music," customers have "hired" a wide range of products: piano rolls, Victrolas, LPs, eight-track tapes, reel-to-reel tapes, cassettes, CDs, MP3 players, and streaming apps. While the products have changed dramatically over time, the job of "creating a mood with music" has never changed, and it will never change.

We can redefine the market from the customer's point of view based on the customer's job.



Navigation App

Get to a destination on time

CRM Software

Acquire new customers

Phlebotomy Tube

Obtain a blood sample

Car Marketplace

Buy/sell a used car

Maintenance Software

Ensure aircraft airworthiness

Networking Device

Enable secure data use


In a B2C market, navigation apps are hired by consumers to "get to a destination on time." In a B2B market, networking devices are hired by CIOs to "enable secure data use" and, in a medical market, a phlebotomy tube is hired by nurses to "obtain a blood sample."

Job Beneficiary and Job Executor

Your key customer is the job beneficiary or the job executor. In consumer markets, the job beneficiary and the job executor are frequently the same.

For example, a consumer (a driver) who is using a navigation app is the executor hiring the app to "get to a destination on time." The driver is also the beneficiary of getting the job done.

In B2B and medical markets, the job executor and the job beneficiary are often different. For instance, a doctor executes the JTBD of "restoring artery blood flow," but the patient is the beneficiary. Similarly, an IT manager may execute the job of "enabling secure data use," but the beneficiaries are company employees.

In many markets, this beneficiary/executor distinction is important because the job executor is currently part of the solution to getting the job done and new solutions will be developed over time to help the beneficiary get the job done on their own without the current executor. Cloud-based applications have enabled companies to reduce or eliminate specialized IT managers (job executors) so that non-technical employees (job beneficiaries) can "enable secure data use" on their own.

In medical markets, new medical devices have been developed to allow a patient to "obtain a blood sample" on their own without a specialized phlebotomist.

Here are some more examples of job beneficiaries and job executors:






Restore blood flow



Manage anger


IT managers

Enable data use



Optimize cash flow



Obtain blood sample


Once you know your key customer (the job beneficiary or job executor) and your customer's job-to-be-done, you have a stable definition of your market that is the basis for your market sizing. So how do you do it?

Estimating Market Size with Jobs-to-be-Done

  1. Identify the job
  2. Identify the job executor and job beneficiary
  3. Estimate the total number of job beneficiaries
  4. Hypothesize the range of willingness to pay (WTP) to get the whole job done among various job beneficiaries by asking market sizing questions in a brief survey
  5. Multiply the WTP by number of job beneficiaries to estimate the market size
  6. If the estimate suggests a large enough market, conduct a survey to validate your willingness to pay hypothesis
  7. Plot the results of the survey on a graph where the y-axis is the “willingness to pay” and the x-axis is the “number of job beneficiaries (customers)”.
  8. Draw a best fit curve through the points on your graph
  9. Calculate the area under the curve

To know if there's an opportunity for your company to capture share in the market you need to identify if there are unmet customer needs in the job and determine if you can satisfy them better than the competition.

If you'd like to try this method for market sizing feel free to reach out to us at thrv for advice on the details. You can also take our online JTBD Course for free.

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