According to the dictionary of the Royal Spanish Academy, “correlation” means “correspondence or reciprocal relationship between two or more things or series of things.” This definition establishes a dependence on correspondence or relationship, not on cause or origin. In disputes related to damage quantification, certain events are sometimes claimed that, while appearing to have a correlational basis, may not necessarily be causally linked. In this sense, there may be claims supported by assertions that may seem very logical and well correlated, but upon being subjected to a contradictory analysis derived from an expert report, it may be demonstrated that there is no direct and immediate causal relationship. This stems from the error of superficially appreciating a causal relationship when what actually exists is only a correlation. In proving the damage, the causal link cannot be inferred from an apparent logical relationship; rather, it requires the action of a technical report that can demonstrate the causal relationship with rigorous qualitative and quantitative analysis.

Causality should only be accepted when it is demonstrated that, to estimate the effects, all causes that may impact different variables have been examined, taking into account the individual impact of each of them, applying the concept of ceteris paribus, and the relationships between different variables within the object of analysis. While in a dispute one of the parties may assert in their claim that there is no doubt about the existence of a causal relationship, as supposedly there would be a direct and immediate consequence of the non-performance of the obligation on the economy of their contract, it is also true that the causal context in which the probability of the damage occurring on the contract economy is examined could be only linear and not encompass all variables that could alter the causal context expressed by the claimant. In this sense, it must always be borne in mind that correlation does not necessarily imply causality.

The analysis of the impact on the variables under study, in demonstrating causality in damage quantification expert reports, often requires comparing the real impacted context against a simulated context where the impact does not exist; this is called a counterfactual scenario. The counterfactual or “but for” analysis observes changes in the process over time and establishes specific qualitative and quantitative criteria of possible outcomes without the occurrence of the impact in order to compare it with the real scenario, with the aim of estimating the quantification of the damage. Some judgments and awards have considered the use of counterfactual or “but for” analysis.

However, it should be noted that there is no clearly established technique for constructing this hypothetical scenario, but we can affirm that the counterfactual analysis has been the referential starting point for the development of different techniques and methodologies in the valuation of quantification in delay and cost damage expert reports, leading to a positive evolution in the development of expert reports in this field, through the evolution of new methodologies that have strengthened progress in this area, and it is expected that they will be consolidated in the future through the contribution of organizations such as the Latin American Circle of Construction Experts – CLAPEC, which aims to be “facilitators of the best methodological standards for the development of expert reports in construction, a mandatory reference in Latin America, from which ideas and knowledge are exchanged through different discussion and debate forums, and the application of the best existing practices related to the development of construction expert reports is promoted.”