How can a disruption affect two product lines that are considered completely independent in risk management? The answer usually lies not in a poor individual assessment, but in a connection that no one was aware of. Every resource in the portfolio was individually assessed, and each one was considered secure. Nevertheless, two plants shut down simultaneously because of a supplier they shared.

The Basic Assumption That No Longer Holds Water

Near-scoring, capacity planning, and criticality assessment each focus on a single resource in isolation, neglecting the network in which it exists. This explains why disruptions can affect multiple, seemingly independent product lines simultaneously, even though each individual assessment was unremarkable. Supply chain risk management fundamentally treats resources as independent units, each assessed separately. This is precisely where the problem lies. The Resource Interaction Approach (RIA) counters this assumption with a different understanding of resources: they are interactive and interconnected, and it is precisely within this network that the reason disruptions propagate differently than predicted by individual assessments lies.

In this article we will show:

• Why Supply Chain Risk Management resources are usually treated as independent and what is overlooked in the process

• What the Resource Interaction Approach specifically states and what it is scientifically based on

• How relationships between companies can be understood as a resource

• What this means for the daily work of purchasing, CPO and management

  
  

Supply Chain Risk Management (SCRM) and the subsequent resilience research (SCRes) generally start from a simple premise: A resource—a supplier, a material, or a production facility—can be assessed in isolation. Its probability of failure, its criticality for production, and the availability of alternative sources are determined, these individual assessments are added together, and an overall picture of portfolio risk is obtained.

This assumption works as long as resources truly operate independently. However, this is rarely the case in interconnected supply chains. Two product lines that, at first glance, appear to have nothing to do with each other, may share the same supplier for a semi-finished product, the same freight forwarder for a critical transport route, or the same testing facility for quality approval. If this one shared resource fails, it affects both lines simultaneously—an effect that an individual assessment of each line cannot capture because it doesn't even consider the interconnectedness of the resources.

Instead of viewing resources as independent, the Resource Interaction Approach (RIA) suggests that companies should consider their interdependence as a starting point, and that relationships between companies should themselves be understood as a resource, not merely a channel through which other resources are procured. This approach has previously been studied in permanent supply chains, temporary construction projects, and research projects before being specifically applied to disruption management.

What the Resource Interaction Approach shows

What does interdependence mean in concrete terms?

According to the RIA, a resource does not have a fixed, intrinsic value. Its value only arises in interaction with other resources and the companies that use them, and can be understood as two-sided. The supplier side can only partially determine the characteristics and potential value of a resource; the rest is determined by the interaction with the user side. In practice, this means that the true value and risk of a supplier only become apparent when considered in the context of the other resources with which it is associated, not when evaluated in isolation.

Why individual ratings overlook these connections

Near-scoring or criticality assessment can be precise and methodologically sound for a single supplier. However, it only evaluates one resource, not the network in which that resource exists. Two suppliers can each have a low individual risk and yet together represent a high risk if they both rely on the same upstream resource, such as the same raw material supplier or the same logistics route. This shared risk doesn't appear in either individual assessment because both assessments end at the boundary of the respective resource. In practice, a glance at the master data of Tier 2 suppliers is often sufficient to reveal this: frequently, several Tier 1 suppliers produce for different plants at the same upstream manufacturer without this information being consolidated anywhere in the procurement system.

Relationships as an independent resource

The RIA distinguishes between permanent and temporary forms of organization. The permanent network of existing supplier relationships provides the resources and relationships that can be mobilized in the event of a disruption. The actual response to a disruption often takes place in a temporary, project-like configuration, comparable to temporary construction or research projects, in which resources from the permanent network are recombined. For example, a secondary supplier that has only been used for small order quantities for years can be scaled up quickly in an emergency because the relationship already existed, meaning that terms and quality standards do not need to be renegotiated. Existing relationships act as latent connections that can be reactivated when needed. This is precisely what makes them a resource in their own right: they offer stability and continuity precisely because they existed before the disruption.

What this means for procurement, CPO and management

For procurement teams, the RIA (Risk Assessment Analysis) means supplementing existing individual risk assessments with a dependency map: Which suppliers, materials, and equipment share upstream resources, even if they are assigned to different product lines? In practice, this can be initiated with a joint workshop in which purchasing, quality assurance, and logistics compare their respective supplier, route, and inspection lists and look for overlaps. This map reveals risk concentrations that are not visible in any individual assessment.

For the CPO, this leads to a different perspective on supplier relationships: they are not merely a means of acquiring materials, but rather a resource in their own right that can be reactivated in case of disruption. This can mean deliberately maintaining a small secondary supplier, even if they have little economic impact, simply to ensure the relationship is resilient in a crisis. Investments in stable, well-maintained relationships therefore pay off even if the specific supplier themselves is not currently facing any increased risk.

For management, the strategic question shifts from "Which suppliers are risky?" to "Where in the network are dependencies concentrated that could affect multiple business units simultaneously?" This question cannot be answered by improving individual assessments, but only by considering the entire network of relationships, for example, in the form of an annual network overview that reveals not only individual risks but also shared dependencies across business units.

Pattern Interrupt

The real bottleneck is rarely the quality of the individual assessments. The real bottleneck is that no one in the company connects the links between the individually assessed resources. Information about shared suppliers, shared logistics routes, and shared testing processes is often scattered across different departments, in the purchasing SRM system, the quality management system, and separate logistics tools.

The most important points in brief

The Resource Interaction Approach demonstrates that resources are wrongly treated as independent in supply chain risk management. Their true value and risk only emerge in conjunction with other resources and the relationships through which they are connected. Procurement teams therefore need a dependency map that goes beyond individual assessments, CPOs need to view relationships as independent resources, and management needs to consider the entire network rather than individual supplier risks.

If you would like to make the dependencies in your own supplier network visible and respond to them jointly at the purchasing, CPO and management levels, please contact us for an initial consultation.