How the Best Strategy Teams Approach Market Sizing
Market sizing and forecasting are essential to market intelligence. They help answer crucial questions about the size and growth rates of any given market.
When conducting market sizing and forecasting, the goal is to chart a path for company growth and make informed decisions about which markets to enter and sustain growth.
Basic concepts in market sizing
What is meant by ‘the market’? In its most basic sense, ‘the market’ is a group of customers buying a certain product or service from the same or similar sellers.
On the flip side, sellers offering similar products and services make up ‘the industry’. Most industries and markets are part of long chains of buyer-and-seller relationships, spanning from B2B connections to the B2C market.
Market sizing helps you uncover potential
Market size is the total volume or value of products and services that an entire industry can sell to a specific group of customers within a defined timeframe, usually annually.
Within the overall market size, there is the addressable market—a specific segment that a company can capture with its offering.
Market sizing is never accurate, but maybe it doesn’t need to be
Accurate market sizing is almost impossible.
There’s a subjective nature to estimation methods, and there’s a significant reliance on assumptions. Moreover, market dynamics rapidly change the size of the market. For example, intensified competition often leads to price declines and corresponding changes in market volume and value.
To make up for the lack of accuracy, it’s important to accept that precise estimates aren’t even necessary. Instead, it’s beneficial to create different forecasting scenarios based on varying assumptions. Remember: it is better to be broadly right than precisely wrong.
The 4 steps of market sizing
Typically, any given market-sizing exercise will follow a four-step pattern:
- Clarify the question and segment the market
- Build the estimation model by breaking the problem down
- Source the data to solve each piece and consolidate
- Validate the results
STEP 1: Clarify the question and segment the market
You want to clearly define the product or service being sized; this is essential. In today’s world, companies always strive to differentiate their offerings. Differentiation makes market sizing very challenging. Because of the ambiguity, you’ll have to make some judgment calls about which products or services to consider as competitors in the same market.
Next, you’ll segment the market to determine the structure of the addressable market. This means breaking down the market by sub-products, applications, customer segments, geographies, and other relevant factors. For example, segmenting the lamp market might involve differentiating technologies (LED, compact fluorescent, incandescent), applications/client segments (industrial, street, commercial, residential), and countries served.
Understanding how market sizing will be used and which segments are crucial for estimation is essential. The cost and time required for data collection are closely linked to the desired accuracy, granularity, and speed of market sizing. If cost and time constraints are high, it’s likely you’ll need to reduce variables or combine categories.
STEP 2: Build the estimation model by breaking the problem down
All methods for estimating market size involve breaking down the problem into smaller parts and combining them to pull out the overall market size. The two principal methods are the ‘top-down approach’ and the ‘bottom-up approach’.
Top-down approach, aka ‘chain ratio method’
The top-down approach estimates the addressable market from above, by starting with a broad market size figure—like an existing market research report for a bigger segment—and narrowing it down to the target market segments by using assumptions and statistics.
Some assumptions can be verified via existing data or statistics, others cannot and have to rely on the best guess or judgment of the market modeler. The top-down approach is usually considered a less robust methodology. It is the “fast and cheap method” of market sizing and tends to give market estimates that are too high.
Bottom-up approach, aka ‘counting noses’
The bottom-up approach estimates the addressable market from below by summing up known data from market participants: usually the supply side or less frequently the demand side.
This approach is often considered more conservative and robust as it takes into account the industry’s capacity limitations. Bottom-up usually requires primary research, making it more accurate but also more costly.
General principles of building the estimation model
To build your estimation model, start by mapping out the available data and comparing it to the product definition and segmentation from step 1.
Then, develop the model by identifying the data gaps and creating a research plan to source the missing data. Use visual aids like flowcharts to assist in understanding the data flow.
STEP 3: Source the data to solve each of the smaller pieces and consolidate into a final result
Secondary and primary research
Sourcing the missing data will take a combination of secondary research, primary research, and analysis.
Secondary research relies on published statistics, existing industry data, product data, news, and company information.
Primary research is conducted through surveys, questionnaires, and expert interviews.
The data collected through these methods is then analyzed.
Analytical tools
Typically, in market sizing, the availability of data can be a major challenge. To bridge the gaps and enhance accuracy, various analytical tools can be employed. Consider using the following methods:
- Heuristic assumptions: Also known as educated guesses or common sense, heuristic assumptions play a vital role in many market studies, even the most highly regarded ones.
- The Delphi method: This judgmental estimation and forecasting method relies on principles like anonymity, iteration, controlled feedback, and weighing. It can provide valuable insights and help with the accuracy of market sizing.
- Regression analysis: By establishing a relationship between an already estimated market size and predictor variables, regression analysis enables quick top-down estimation of additional data points. Predictors can include GDP, demographic and geographic variables, industry production, imports and exports, and the market size of related products or services.
These analytical tools, when applied strategically, can fill data gaps and provide more reliable market estimates.
STEP 4: Validating the results
After gathering the missing data and incorporating it into your model, it’s very important to validate the results to ensure their accuracy.
The validation process consists of two steps:
Thorough checking of the model and inputs
Begin by conducting a quick, comprehensive review of the model you used, including the inputs, assumptions, calculations, and sources.
Pay close attention to the product definitions, segmentation, and other crucial factors. Perform ‘sanity checks’ to ensure the overall coherence and reliability of the model. This is a GREAT time to conduct a sensitivity analysis, where you test the model by using the highest and lowest possible values for uncertain assumptions.
Triangulation – building a model with multiple approaches
Triangulation is a powerful technique where you use two or three different approaches to estimate the same variable. By employing disparate sources of data and independent estimation methods, you’re able to cross-validate your estimates and increase their reliability. Triangulation reinforces confidence in your market sizing results while ensuring consistency in product definition and segmentation.
The validation process should ultimately provide you with the assurance and certainty needed to derive similar market estimates from multiple methods or sources.
Market sizing is only as good as the intelligence behind it
Valona combines AI-powered market monitoring with quantitative financials so your market models are built on current, validated data, not stale reports.
Explore Valona’s market intelligence platform
Frequently Asked Questions about market sizing
What is market sizing and why does it matter?
Market sizing is the process of estimating the total volume or value of a market — how many customers exist, how much they spend, and how fast that’s growing. It matters because it’s the foundation of any serious strategic decision: entering a new market, setting growth targets, prioritizing product investment, or making the case to leadership for resources. Without a reliable market size estimate, you’re guessing.
What’s the difference between TAM, SAM, and SOM in market sizing?
These three terms define how much of a market you can actually reach:
- TAM (Total Addressable Market) — the full theoretical market for your product or service
- SAM (Serviceable Addressable Market) — the portion of TAM you can realistically serve given your current model, geography, and offer
- SOM (Serviceable Obtainable Market) — the slice of SAM you can realistically capture in a defined timeframe
Market sizing usually starts with TAM and narrows down. The SOM is what matters most for business planning.
What’s the difference between top-down and bottom-up market sizing?
Top-down market sizing starts with a broad industry figure and narrows it using assumptions and ratios — it’s faster and cheaper, but tends to produce inflated estimates. Bottom-up sizing starts from real data points (customer counts, unit prices, transaction volumes) and builds upward — it’s slower and more expensive, but considerably more reliable. Most rigorous market sizing exercises use both, then triangulate.
How accurate does market sizing need to be?
Less accurate than most people assume. The goal isn’t a precise number but a defensible range built on transparent assumptions. Markets change fast; a market size figure that was correct six months ago may already be outdated. What matters is whether your methodology is sound and your assumptions are clearly documented. As a rule: it’s better to be broadly right than precisely wrong.
What data sources are used in market sizing?
Market sizing draws from two main sources:
- Secondary research: Published market reports, trade associations, company filings, government statistics, news, and product data
- Primary research: Expert interviews, customer surveys, and supplier conversations
The challenge is that data gaps are common, especially in niche or fragmented markets. That’s where analytical tools like heuristic assumptions, the Delphi method, and regression analysis help bridge the gaps.
How does market sizing support competitive intelligence?
Market sizing and competitive intelligence are closely connected. Knowing total market value lets you benchmark competitor revenue against potential share. It reveals whether a market is growing or consolidating and which players are gaining ground. When integrated with competitive monitoring, market sizing becomes a live tool for tracking share shifts, not just a one-time exercise.
How can an intelligence platform help with market sizing?
Most market sizing exercises slow down at the same point: secondary research. Finding the right industry data, tracking down competitor financials, monitoring trade flows across geographies — it’s time-intensive and the data goes stale fast. Valona addresses this differently than most platforms. Beyond AI-powered monitoring of 200,000+ global sources for the qualitative signals that feed market models, Valona also offers something rare: pre-built quantitative industry data models — market sizing datasets, competitor financial benchmarking, and trade flow analysis — built specifically for complex global industries. It’s the only platform that combines real-time qualitative intelligence with validated quantitative market data in one place, so your market estimates are built on current information, not last year’s report.
