Models of Organisational Buying Behaviour: Buy Grid and Fisher’s Model

When businesses make purchasing decisions, they follow surprisingly structured paths. Unlike individual shoppers who might buy a pair of shoes on impulse, companies need frameworks that help them navigate complex buying situations. Two influential models have shaped how we understand these decisions: the Buy Grid Model and Fisher’s Model. These frameworks help organizations recognize what type of purchase they are facing and who should be involved in the decision, making the entire process more strategic and less chaotic.

The Buy Grid Model: mapping the purchasing journey 🔗

Picture a matrix that captures both the journey and the situation of every organizational purchase. That is exactly what Robinson, Faris, and Wind developed in 1967 when they introduced the Buy Grid Model. This framework treats industrial buying not as isolated transactions, but as organizational decision-making processes where multiple people collaborate on a single purchase.

The model works by creating a grid with two dimensions. On one side, you have the buy phases, which are the eight steps a company moves through when making a purchase. On the other side, you have the buy classes, which are three different types of buying situations. When you cross-reference these two dimensions, you get a comprehensive picture of where your organization stands in any purchasing decision.

The eight buy phases: your step by step guide 🔗

Every organizational purchase moves through a series of distinct stages. The eight buy phases identified by researchers include recognizing the problem or need, determining what characteristics and quantities are needed, describing these specifications, searching for potential suppliers, acquiring and analyzing proposals, evaluating proposals and selecting suppliers, establishing an order routine, and finally conducting performance feedback and evaluation.

Think about a company that realizes its air conditioning system keeps breaking down. That realization is phase one. Next, they determine they need a system that can cool 5,000 square feet efficiently. Then they write out detailed specifications about energy efficiency and cooling capacity. The process continues until they have not only purchased and installed the system but also evaluated how well it performs over time.

The three buy classes: understanding your situation 🔗

Not all purchases are created equal. The Buy Grid Model categorizes purchases into three distinct situations. A new task occurs when an organization makes its first purchase for a completely new need. This is the most complex situation, requiring extensive information gathering and evaluation. For example, a manufacturing company buying its first automated assembly line faces a new task.

A modified rebuy happens when the company wants to repurchase something but with changes to specifications, suppliers, or terms. Maybe that office supply company decides to upgrade its printers with better models or negotiate different terms with current suppliers. Finally, a straight rebuy is the simplest situation where a company routinely orders the same product under the same conditions, like restocking paper supplies monthly from the same trusted vendor.

Why the Buy Grid Model matters and where it falls short 🔗

The real power of the Buy Grid Model lies in helping businesses understand process complexity and identify their buying center. Marketing professionals can use it to deliver the right message at the right time, while purchasing teams can better structure their approach based on which cell of the matrix they occupy.

However, the model has notable limitations. It lacks strong predictive ability because real-world decisions involve organizational culture, politics, and interpersonal dynamics that a matrix cannot fully capture. The model also assumes purchasing decisions are largely rational and systematic, but anyone who has worked in an organization knows that personal relationships, emotions, and internal politics often influence outcomes. Additionally, the framework tends to neglect the supplier’s perspective and focuses primarily on products rather than services.

Fisher’s Model: when complexity meets uncertainty 🔗

While the Buy Grid Model provides structure to the purchasing process, Fisher’s Model takes a different approach by examining two critical factors that influence every buying decision: product complexity and commercial uncertainty. These two dimensions interact to determine how organizations approach their purchases.

Understanding product complexity 🔗

Product complexity refers to how complicated a product is in terms of features, specifications, and usage. Highly complex products like industrial machinery or advanced technology solutions demand detailed decision-making processes. Organizations typically engage in extensive research, consultations, and even pilot testing before committing to such purchases. These products may require customization or integration with existing systems, which adds layers to the decision.

On the flip side, simpler products with standardized features require less evaluation effort. Basic office supplies or simple software can be purchased through faster, less involved processes.

Navigating commercial uncertainty 🔗

Commercial uncertainty captures the risk or unpredictability surrounding a buying decision. This could involve market volatility, fluctuating prices, changing supplier reliability, or unexpected complications. In highly uncertain environments, organizations adopt more cautious buying behaviors. They might seek longer-term relationships with established suppliers, negotiate flexible terms, or explore multiple supplier options to spread risk.

Imagine purchasing equipment for a new product line in an unstable market. The organization would likely be risk-averse, preferring well-established suppliers or negotiating terms that account for potential future market shifts.

The four quadrants of Fisher’s Model 🔗

When you map product complexity against commercial uncertainty, you create four distinct quadrants, each requiring different emphasis. In situations with low complexity and low uncertainty, the buyer emphasis should dominate. The purchasing department can handle these decisions efficiently with minimal involvement from other departments.

When uncertainty is high but complexity remains low, policy maker emphasis becomes crucial. Senior management needs to be involved because the commercial risks require strategic consideration, even though the product itself is straightforward.

The third quadrant features low uncertainty but high complexity, demanding technological emphasis. Technical experts and engineers must play central roles because understanding the product’s intricacies is paramount, while the commercial environment remains relatively stable.

Finally, when both uncertainty and complexity are high, total involvement is necessary. Multiple departments, senior leadership, technical experts, and purchasing professionals must all collaborate to navigate both the product’s complexity and the risky commercial environment.

Seeing Fisher’s Model in action 🔗

Consider the example of purchasing a Pragati cooler for an office. This product has low complexity as air coolers are relatively simple devices with straightforward specifications. The commercial uncertainty is also low because the cooler market is stable, with predictable pricing and reliable suppliers. This purchase falls squarely into the “buyer emphasis” quadrant.

In this situation, the purchasing department takes the dominant initial role. They can identify suitable models, compare prices, check delivery times, and make the purchase without extensive involvement from senior management or technical teams. The decision moves quickly and efficiently because neither the product nor the commercial environment presents significant challenges.

Using these models together 🔗

The Buy Grid Model and Fisher’s Model complement each other beautifully. The Buy Grid helps you understand where you are in the purchasing process and what type of buying situation you face. Fisher’s Model then helps you determine who should be involved and how much emphasis different stakeholders should place on the decision.

Together, these frameworks transform organizational purchasing from a chaotic, ad hoc process into a strategic, structured approach. They help businesses allocate resources efficiently, involve the right people at the right time, and make better-informed decisions. While neither model perfectly predicts every real-world scenario because human behavior and organizational politics add complexity, they provide invaluable starting points for understanding and improving how organizations buy.

What do you think? Have you encountered purchasing decisions in your organization that fit neatly into these models, or have you seen situations where human factors completely upended the rational frameworks? How might these models need to evolve to better account for the digital transformation and rapid market changes we see today?

References

1. https://www.provenmodels.com/549/buygrid-framework/c.-w.-faris–patrick-robinson–yoram-wind
2. https://professionalshiksha.blogspot.com/2017/03/buygrid-model-of-industrial-buying.html
3. https://slm.mba/mmpm-001/models-of-organisational-buying-behaviour/