artificial-intelligence

Evidence-Based Valuation: Reconciling Property, Planning, Economic, and Market Evidence

On June 18, 2026, I had the privilege of speaking before the members of the Philippine Real Estate Service Practitioners, Inc. (PhilRES) – Mandaue City Chapter during its 6th General Membership Meeting held at Mandani Bay, Mandaue City. My presentation focused on a subject that has occupied much of my professional work in recent years: Evidence-Based Valuation (EBV) for Litigation, Expropriation, and Just Compensation.

For decades, real estate valuation has relied heavily on the Sales Comparison Approach. Comparable sales remain an important source of market evidence and continue to be one of the most widely accepted methods of determining value. However, in many assignments—particularly expropriation cases, litigation matters, infrastructure projects, and complex property disputes—the question often arises: Is market evidence alone sufficient to explain value?

The traditional appraisal process frequently emphasizes numerical adjustments derived from comparable transactions. While mathematically sound, such an approach may not fully capture the broader factors that influence value. Infrastructure investments, zoning regulations, land use policies, economic growth, scarcity, accessibility, environmental conditions, and development potential all contribute to the creation of value long before they are reflected in actual market transactions.

This observation led to the development of a framework I refer to as Evidence-Based Valuation (EBV).

The central premise of EBV is straightforward: value conclusions should not rely solely on comparable sales but should be supported by the reconciliation of multiple forms of evidence. These include:

Property Evidence – the physical characteristics of the property such as location, area, shape, topography, accessibility, improvements, and development potential.

Planning Evidence – land use plans, zoning classifications, infrastructure projects, government policies, and regulatory controls that influence future utility and development.

Economic Evidence – demand and supply conditions, growth trends, scarcity, investment activity, income potential, and broader economic drivers.

Market Evidence – comparable sales, listings, market transactions, and investor behavior.

These forms of evidence are not independent of one another. Rather, they interact to influence the highest and best use of a property, which ultimately forms the basis of value.

The concept is equally relevant in both ordinary valuation assignments and special-purpose engagements. Evidence-Based Valuation strengthens the foundation of value conclusions by integrating multiple forms of evidence beyond comparable sales alone. Even in ordinary market valuations, appraisers are expected to provide conclusions that are not only supported by comparable sales but also grounded in a thorough understanding of the property’s characteristics, planning context, and economic environment. Courts are often asked to determine compensation that is fair not only to the government but also to the property owner. In such situations, the challenge is not merely selecting a comparable sale but reconciling all available evidence to arrive at a value conclusion that is credible, transparent, and defensible.

Evidence-Based Valuation does not seek to replace established valuation approaches. Instead, it seeks to strengthen them by expanding the evidentiary foundation upon which value conclusions are formed. Comparable sales remain important, but they should be viewed as one component of a broader evidentiary framework rather than the sole determinant of value.

As valuation professionals, we are increasingly called upon to explain not only what a property is worth, but also why it is worth that amount. This requires a deeper examination of the factors that create, sustain, and influence value.

The EBV framework remains a continuing work in progress. Future developments will explore its application to litigation valuation, water rights valuation, infrastructure projects, feasibility studies, market analysis, and just compensation determinations. The objective is not to create complexity for its own sake, but to improve transparency, strengthen professional judgment, and provide decision-makers with more defensible valuation conclusions.

Ultimately, valuation is not merely a mathematical exercise. It is the process of evaluating evidence, reconciling competing perspectives, and arriving at a reasoned conclusion. In that sense, evidence is not an alternative to valuation—it is the foundation upon which valuation rests.

Value is created before it is measured.

Monterrazas and the Tragedy of the Commons

Why System Thinking Requires Stricter Development Standards

Recent public discussions have reflected different perspectives on the Monterrazas development in Cebu City, including system-level explanations, precautionary considerations, and calls for regulatory review. These illustrate the complexity of decision-making in such contexts.

At first glance, the issue may appear as a familiar tension between development and environmental protection. However, it may be more accurately understood through a different lens.

From an economic perspective, what this situation reflects is a form of the Tragedy of the Commons.

The concern lies in understanding how multiple developments interact within a shared system, and how each contributes to cumulative impacts over time.

Cebu’s upland areas perform essential ecological functions. They absorb rainfall, regulate runoff, and contribute to the stability of downstream communities. These functions do not operate within the boundaries of individual properties. They extend across space, linking different parts of the city through continuous hydrological processes.

In this context, the question of whether a particular development lies within or outside a defined watershed boundary, while relevant in technical terms, does not fully resolve the issue. Environmental systems do not operate as isolated compartments. Their behavior reflects interaction rather than separation.

The scale of that interaction is often difficult to grasp in abstract terms.

Evidence from watersheds within Metro Cebu further clarifies how this system operates—and how development must be understood within it.

Studies of the Mananga watershed show that land-use and land-cover changes—particularly in upstream areas—affect infiltration, surface runoff, and the movement of water across the system. As vegetation is reduced or land is altered, less water is absorbed and more becomes surface flow.

A similar pattern is observed in the Butuanon River watershed. The river originates in upland areas of Cebu City and flows through increasingly urbanized zones before reaching the coast. Upstream areas are already characterized by agricultural and altered land uses, while downstream sections are densely developed. This configuration illustrates how water accumulates as it moves across elevations, shaped by both upstream conditions and downstream constraints.

Altogether, these cases point to a consistent principle:

The watershed is the system within which individual projects must be considered, as runoff is generated across the entire catchment while its behavior is shaped by land-use conditions across different elevations.

This framing is critical. It does not assign causation to any single location. Rather, it defines the proper unit of analysis.

A project is not evaluated in isolation, but in relation to the system it enters—where each intervention contributes to cumulative pressures and must therefore be assessed with reference to the system’s capacity.

It is often observed that flooding in Cebu is multi-causal. Infrastructure limitations, watershed conditions, land-use changes, and rainfall patterns all contribute. This observation is correct.

However, its implication must be properly understood.

If multi-causality is interpreted to mean that no single development can be meaningfully evaluated, then responsibility becomes diffused. Multiple factors contribute, yet accountability becomes less clearly defined.

But the correct implication is the opposite.

If risk is systemic, then evaluation must also be systemic—and correspondingly more rigorous.

The system is not an excuse—it is the basis for stricter evaluation.

This requires a shift in how development decisions are made.

The relevant question is not whether a particular project can be shown to cause a specific flooding event. Rather, it is whether the addition of that project contributes, in combination with others, to increasing pressure on a system that may already be approaching its limits.

The concern lies in the combined effects within a shared system, and in how each individual project contributes to those cumulative impacts.

This leads to a central question:

What is the capacity of the system?

How many developments are already present within a given environmental zone?
To what extent has land use already been altered?
At what point does additional development begin to significantly affect the system’s ability to absorb rainfall and regulate runoff?

Without a clear understanding of these limits, development decisions are made incrementally, without reference to cumulative thresholds.

The Monterrazas issue, therefore, should be viewed in terms of how development decisions are made when each additional project contributes to a system with finite capacity.

In such a context, compliance at the project level is no longer sufficient. Each additional intervention must be evaluated in relation to the condition of the system as a whole.

This has significant implications for urban development.

First, evaluation must move beyond individual projects toward system-level analysis.

Second, development must be aligned with capacity. Growth is no longer simply a matter of feasibility or compliance, but of whether the system can sustain additional pressure.

Third, planning must shift from reactive to anticipatory. Addressing impacts only after they occur is both inefficient and costly.

Fourth, institutional coordination must ensure that decisions reflect a consistent understanding of cumulative risk.

The Monterrazas issue is not resolved by determining whether it falls within a particular boundary, nor by isolating it from broader conditions.

It must be understood as part of a system where effects accumulate, capacity is finite, and each development contributes to increasing pressure on that system.

It shows that outcomes in shared systems are shaped not only by individual decisions, but by how those decisions accumulate—and whether they are governed by a clear understanding of limits.

Ultimately, the question is not whether a particular project should proceed or not.

It is whether each project is evaluated in light of the system it enters—and whether that system can sustain the additional burden it brings.

Because in such systems, urban development is no longer simply about what can be built.

It is about how each development contributes to a shared environment—and whether the whole remains within its capacity to endure.

Why Effective Report Writing Adds Value

In the practice of real estate appraisal, much emphasis is often placed on the technical process of valuation—data collection, market analysis, and the application of valuation approaches. However, as Mr. Gus Agosto emphasized in a recent lecture on Appraisal Report Writing, one of the most overlooked yet indispensable components of the appraisal process is the ability to clearly and effectively communicate its outcome. Effective appraisal, as he asserts, means effective reporting.

Drawing from over a decade of experience in the field, Mr. Agosto highlighted that writing an appraisal report is not merely a clerical task or an afterthought to technical valuation. It is the final product—the formal articulation of an appraiser’s professional opinion of value. This report must not only present data but must also comply with standards, reflect sound judgment, and demonstrate adherence to the legal and ethical expectations of the profession.

Some appraisal reports currently in circulation—particularly those used as templates—were created prior to the passage of Republic Act No. 9646, known as the Real Estate Service Act of the Philippines (RESA Law). Others are adapted from international formats that may not fully conform to Philippine legal and regulatory requirements. While these templates may serve as useful starting points, Mr. Agosto stressed that they are insufficient if not updated to reflect local laws and contemporary standards. Over the past decade, numerous laws and administrative issuances have been enacted, including the Philippine Valuation Standards (PVS), Data Privacy Act, Electronic Commerce Act, Anti-Money Laundering Act, updates to BIR Revenue Regulations, and court procedural rules, which must now be reflected in appraisal report writing.

Under Section 3(g) of the RESA Law, a real estate appraiser is legally defined as a professional who “performs or renders, or offers to perform services in estimating and arriving at an opinion of or acts as an expert on real estate values,” and whose services “shall be finally rendered by the preparation of the report in acceptable written form.” This statutory requirement emphasizes that the report is not a mere formality; it is the legal expression of the appraiser’s findings and professional responsibility.

Further, Section 5(c) of the Implementing Rules and Regulations (IRR) of R.A. 9646 mandates that licensed appraisers shall “prepare, sign, and issue a real estate appraisal report” in accordance with accepted principles and standards prescribed by the Board and the Professional Regulation Commission (PRC). The PVS, aligns with the International Valuation Standards (IVS) but is tailored to Philippine law and practice. Reports must demonstrate transparency in methodology, accuracy in assumptions, and consistency in legal compliance.

Mr. Agosto also pointed out that appraisal reports are not generic in nature. They must be purpose-specific, as each type of valuation engagement—litigation, insurance, sales, taxation, lease, or expropriation—carries distinct reporting requirements, legal standards, and evidentiary burdens. Moreover, Mr. Agosto emphasized that the appraiser’s ability to communicate effectively, through proper grammar, structure, and clarity, is just as important as analytical rigor. A report written in poor language or filled with jargon may undermine its credibility, even if technically correct. Thus, he encourages appraisers to continually upskill in both technical and language proficiency, utilize digital tools, apply peer review, and align with style guides that enhance report readability and presentation.

Appraisal reports serve as vital documents in court cases, bank financing, taxation, and public policy. Thus, Mr. Agosto explained, they must be credible, compliant, and defensible. This requires not only legal and technical knowledge, but also proficiency in professional communication. The appraiser must be able to clearly convey complex data, defend conclusions logically, and eliminate ambiguity through proper grammar, sentence structure, and vocabulary. In an era where reports are often read by legal, financial, and lay audiences alike, the precision and clarity of language can determine whether the report is useful—or even admissible.

Hence, appraisal report writing is not just a skill—it is a professional obligation grounded in law, ethics, and service to the public good. It transforms raw valuation data into a structured, credible, and actionable opinion of value. As Mr. Agosto aptly concluded: “Your report is your professional signature. It must speak with competence, integrity, and purpose long after you’ve signed it.”