Decision-Stage Evidential Sufficiency in Planning – Governance Principles
A Methodological Examination of Evidence Availability, Deferral, and Reconstruction
1. Introduction
Public local authority planning decisions are required to be made on the basis of material considerations supported by evidence that exists, is accessible, and is capable of being relied upon at the point of determination. While extensive documentation may accompany a planning application, the presence of documents alone does not guarantee that decision-critical evidence is complete, decision-grade, or lawfully deferrable.
In practice, the distinction between information that exists and evidence that is sufficient for decision-making is not always explicit. Committee reports summarise large volumes of material, statutory consultee responses are often condensed, and complex technical matters are frequently framed as capable of resolution through future conditions. These practices are commonplace and are not, in themselves, indicative of error. However, they can obscure an important question: whether the evidence relied upon at the moment a decision is taken is sufficient to support that decision in law.
This paper examines what is referred to here as decision-stage evidential sufficiency — the requirement that, at the time a decision is made, the evidence necessary to assess material considerations is present, usable, and not deferred beyond what the legal and policy framework permits. The focus is not on whether a particular planning outcome is desirable, but on whether the decision-making process is capable of being reconstructed and justified by reference to evidence that demonstrably existed at the relevant time.
The analysis does not attribute fault, intent, or competence to any authority, officer, or decision-maker. Nor does it seek to revisit the planning merits of individual cases. Instead, it explores a recurring methodological problem: that evidential absence, partial completion, or reliance on future assessment is often difficult to identify without structured reconstruction of the decision record. Where such reconstruction is not undertaken, gaps may remain unnoticed even in otherwise conscientious decision-making environments.
The purpose of this paper is therefore threefold:
- To describe a method for testing decision-stage evidential sufficiency in a systematic and repeatable way.
- To identify common patterns by which evidential insufficiency can arise without being immediately apparent.
- To explain why these patterns are difficult to detect through conventional professional review alone.
By approaching the issue at the level of method rather than outcome, this paper aims to contribute to a clearer understanding of how evidence functions at the point of determination, and how decision-making processes might be more transparently assessed without presupposing error or impropriety.
2. Defining Decision-Stage Evidential Sufficiency
For the purposes of this paper, decision-stage evidential sufficiency is defined as the condition in which all evidence necessary to assess material considerations exists, is accessible, and is capable of being relied upon at the moment a planning decision is taken.
This concept is distinct from the broader existence of background information, supporting documentation, or future assessment frameworks. A decision may be accompanied by extensive documentation while still lacking evidence that is sufficiently complete, resolved, or decision-grade at the point of determination. Evidential sufficiency therefore concerns timing, completeness, and usability, rather than volume.
2.1 The Decision Moment as a Legal and Analytical Boundary
Planning decisions are events, not processes extended indefinitely through post-decision stages. While conditions, obligations, and subsequent approvals may legitimately address certain matters, public law requires that the decision itself be capable of justification by reference to evidence available at the time it was made.
Decision-stage evidential sufficiency therefore treats the committee meeting or delegated decision point as a fixed analytical boundary. Evidence that is incomplete, indicative, or contingent on future work must be assessed against whether deferral is lawful and appropriate for the topic in question. Where such deferral is not permitted, the absence of completed evidence at decision stage becomes analytically significant.
2.2 Evidence Versus Information
For clarity, PGAT is not designed to assess planning balance or merits, determine compliance or non-compliance with policy or law, reach conclusions as to procedural propriety or impropriety, or replace professional judgment or legal analysis. Its role is confined to assisting review of the documented record as presented.
A central source of confusion in decision analysis arises from the conflation of information with evidence.
For the purposes of this paper;
- Information refers to descriptive material, scoping documents, intentions, or preliminary assessments that outline what may be done in the future.
- Evidence refers to completed assessments, analyses, or conclusions that are capable of supporting or constraining a planning judgment at decision stage.
3. Common Failure Modes in Decision-Stage Evidence
When decision-stage evidential sufficiency is examined systematically, a number of recurring failure modes can be identified. These do not arise from any single cause, nor do they imply error or impropriety. Rather, they reflect structural features of how complex technical material is assembled, summarised, and presented at the point of determination.
The failure modes described below are analytical categories. They are intended to assist in identifying where evidential sufficiency may warrant closer examination, not to assert that a particular decision outcome was incorrect.
3.1 Indicative Material Substituted for Decision-Grade Evidence
One of the most common failure modes is the reliance on material that is explicitly described as indicative, preliminary, or subject to further work, in circumstances where decision-grade evidence is required.
Indicative material may:
- outline potential mitigation approaches;
- describe intended methodologies; or
- provide high-level feasibility statements.
While such material can be useful in scoping or early engagement stages, it does not, by itself, constitute evidence capable of resolving decision-critical matters where policy or law requires assessment at determination stage.
The failure mode arises not from the existence of indicative material, but from its treatment as if it were equivalent to completed assessment.
3.2 Lawful Deferral Assumed Rather Than Demonstrated
A second recurring pattern involves the assumption that unresolved matters can be addressed through conditions, without explicit analysis of whether deferral is lawful for the topic in question.
This failure mode typically involves:
- identifying a constraint or uncertainty;
- asserting that it can be resolved post-decision; and
- proceeding without demonstrating why deferral is permissible at that stage.
Decision-stage evidential sufficiency requires more than the availability of a condition. It requires a reasoned basis for concluding that deferral does not undermine the ability to assess the material consideration at the time of determination.
Where that reasoning is absent or implicit, evidential sufficiency may be weakened even if a condition is ultimately imposed.
3.2 Lawful Deferral Assumed Rather Than Demonstrated
Statutory consultee responses often contain nuanced positions, conditional acceptability, or unresolved objections. A common failure mode arises when this nuance is compressed into simplified summaries that alter the practical meaning of the response.
Examples of compression include:
- treating “no objection subject to…” as “no concern”;
- omitting the scale or dependency of required mitigation;
- reframing unresolved objections as matters of routine detail; or
- abstracting site-specific concerns into generalised assurances.
This failure mode is typically unintentional and driven by the need for clarity and brevity. However, where compression obscures the substantive position of a consultee, Members may not be presented with decision-stage evidence in its full and accurate form.
3.4 Background Documentation Mistaken for Evidential Resolution
Another frequent issue arises where the existence of background reports, appendices, or technical documents is taken as evidence that a matter has been resolved, without assessing whether those documents actually address the decision-stage question.
This failure mode occurs when:
- reports are descriptive rather than analytical;
- assessments identify constraints without resolving them;
- data is presented without conclusions; or
- evidence is historical, generic, or not site-specific.
Decision-stage evidential sufficiency requires that documentation does more than exist; it must answer the material question being relied upon at the point of decision.
3.5 Absence Masked by Narrative Assurance
In some cases, evidential absence is not explicit but is masked by confident narrative language. Phrases such as “satisfactorily addressed”, “can be managed”, or “will be resolved” may appear in summaries without corresponding reference to completed assessments.
This failure mode is particularly difficult to detect because:
- the language suggests resolution;
- the absence is implicit rather than stated; and
- the reassurance substitutes for evidential demonstration.
Where narrative assurance replaces evidential explanation, reconstructing the decision record becomes more difficult, even when no misrepresentation is intended.
3.6 Inconsistent Treatment of the Same Evidence Base
A further failure mode involves the selective treatment of the same evidence base in different contexts. For example, an emerging policy or supporting study may be relied upon to support one aspect of the planning balance, while being dismissed as carrying no weight when raised as a constraint.
This internal inconsistency does not necessarily reflect conscious contradiction. It often arises from:
- different speakers addressing different questions;
- shifts between written reports and oral updates; or
- the absence of a single, explicit evidential framework.
While such material can be useful in scoping or early engagement stages, it does not, by itself, constitute evidence capable of resolving decision-critical matters where policy or law requires assessment at determination stage.
The failure mode arises not from the existence of indicative material, but from its treatment as if it were equivalent to completed assessment.
3.2 Lawful Deferral Assumed Rather Than Demonstrated
A second recurring pattern involves the assumption that unresolved matters can be addressed through conditions, without explicit analysis of whether deferral is lawful for the topic in question.
This failure mode typically involves:
- identifying a constraint or uncertainty;
- asserting that it can be resolved post-decision; and
- proceeding without demonstrating why deferral is permissible at that stage.
Nevertheless, inconsistent treatment complicates reconstructability and weakens the clarity of the decision-stage evidential position.
3.7 Why These Failure Modes Persist
These failure modes persist not because of negligence, but because:
- evidence is distributed across large and complex records;
- summaries are necessary but reductive;
- time at decision stage is limited; and
- professional review often focuses on outcomes rather than evidential state at a fixed moment.
Without a structured method for testing decision-stage evidential sufficiency, these patterns can recur across otherwise unrelated decisions.
3.8 Evidential Asymmetry Across Scrutiny Stages
Observation of planning decision records indicates a marked asymmetry in the volume and depth of evidence produced at different stages of scrutiny.
In routine determinations, the evidential record is often relatively limited, commonly consisting of a small number of core documents sufficient to support a decision in the absence of sustained challenge. Where decisions proceed without appeal or significant objection, the evidential footprint typically remains modest.
By contrast, where an application is appealed, subject to extensive objection, or otherwise exposed to heightened scrutiny, the evidential record often expands substantially. In such cases, large volumes of additional documentation may be generated, including technical assessments, expert reports, clarifications, and rebuttal material that were not present at the original decision stage.
This pattern suggests that evidence production in planning is, to a significant extent, reactive rather than exhaustive. The absence of extensive evidence at determination stage does not imply that such evidence could not exist, but that it was not considered necessary to produce it under conditions of limited contestation.
The analytical significance of this asymmetry is that the sufficiency of the decision-stage evidential record is frequently assessed only once scrutiny intensifies. Where scrutiny remains low, evidential sufficiency is more likely to be presumed. Where scrutiny increases, verification replaces presumption, and the evidential record correspondingly expands.
4. Why Conventional Professional Review Rarely Detects These Patterns
The failure modes described in Section 3 are not obscure, nor do they depend on technical ignorance. They persist because conventional professional review is not designed to test decision-stage evidential sufficiency as a discrete analytical problem. Instead, existing review practices are oriented toward outcomes, reasonableness, and procedural compliance in the broad sense, rather than reconstruction of the evidential state at a fixed decision point.
This section explains why well-established professional processes can overlook decision-stage evidential insufficiency even when acting diligently and in good faith.
4.1 Outcome-Focused Review Masks Evidential State
Most professional review processes, whether undertaken by planners, inspectors, or legal advisers, are framed around the question of whether a decision is defensible rather than whether the evidential state at the moment of decision was complete.
This distinction matters. A decision may appear reasonable when viewed in light of subsequent submissions, clarifications, or assumed future compliance, even if decision-grade evidence was incomplete at determination stage. When review focuses on whether a decision could be defended overall, evidential absence at the precise decision moment may be subsumed within a broader narrative of acceptability.
As a result, evidential insufficiency is often interpreted retrospectively as a matter of planning judgment rather than identified contemporaneously as an analytical gap.
4.2 Incremental Reading Obscures Absence
Professional review is typically conducted incrementally, through selective reading of reports, summaries, appendices, and correspondence. This approach is efficient and necessary given the volume of material involved, but it carries an inherent limitation: absence is difficult to detect without deliberate reconstruction.
When review proceeds by sampling or prioritisation, the existence of some material in a topic area can be taken as proxy for sufficiency. The question “what is missing?” is rarely asked explicitly unless prompted by contradiction or complaint.
Decision-stage evidential sufficiency, by contrast, requires a negative test: the identification of what does not exist but would be required to support reliance on a material consideration.
4.3 Deference to Professional Narratives
Committee reports and officer presentations necessarily involve professional judgement in summarising complex technical matters. Review processes often defer to these narratives, particularly where they are expressed confidently and appear internally coherent.
This deference is not misplaced; it reflects trust in professional competence. However, narrative coherence can mask evidential absence where:
- conclusions are stated without reference to completed assessments;
- future work is implied to be routine; or
- uncertainty is reframed as manageability.
Where review accepts narrative assurance as indicative of evidential resolution, the underlying evidential state may not be interrogated in detail.
4.4 Temporal Diffusion of Responsibility
Decision-making in planning is distributed across time and actors. Evidence may be prepared by one party, summarised by another, presented by a third, and relied upon by decision-makers who are not involved in its production.
This temporal and organisational diffusion makes it difficult for any single reviewer to hold a complete mental model of:
- what evidence existed at the time of decision;
- what evidence was anticipated but incomplete; and
- what was assumed to follow post-decision.
Without a structured method for fixing the decision moment as an analytical boundary, review naturally drifts toward an aggregated understanding rather than a time-specific reconstruction.
4.5 Legal Review Prioritises Arguability Over Reconstruction
Legal review, particularly in the context of challenge or defence, is often concerned with whether an argument can be made, rather than whether the evidential record was complete in fact.
This is not a deficiency of legal reasoning; it reflects the adversarial context in which such review occurs. However, it means that:
- evidential gaps may be reframed as matters of weight;
- absence may be argued as implicit resolution; and
- uncertainty may be presented as permissible judgement.
Where review is oriented toward arguability, systematic reconstruction of the evidential state at decision stage is not always undertaken unless strictly necessary.
4.6 The Absence of a Formal Reconstruction Method
Most significantly, there is no widely adopted, formal method for reconstructing the evidential state of a decision at the moment it was taken.
Without such a method:
- review relies on professional intuition;
- patterns across cases remain invisible; and
- similar failure modes can recur without recognition.
This does not reflect a lack of diligence. It reflects a gap in analytical tooling and methodology.
4.7 Implication
The persistence of decision-stage evidential insufficiency is therefore not best explained by individual failure, but by a structural misalignment between how decisions are made and how they are later reviewed.
Where review processes are not explicitly designed to test decision-stage evidential sufficiency, the absence of decision-grade evidence may remain undetected even in systems that are otherwise robust, conscientious, and procedurally compliant.
5. What Systematic Reconstruction Enables
Treating decision-stage evidential sufficiency as an explicit analytical problem, rather than an implicit professional judgement, enables forms of insight that are otherwise difficult or impossible to obtain. These insights do not depend on hindsight, disagreement with outcomes, or assumptions about intent. They arise solely from fixing the decision moment as a boundary and reconstructing the evidential state that existed at that point.
This section describes what systematic reconstruction makes visible, and why these effects cannot be reliably achieved through conventional review alone.
5.1 Separation of Outcome from Evidential State
Systematic reconstruction allows the evidential state of a decision to be examined independently of its outcome.
This separation is critical. Outcomes often influence retrospective interpretation: a decision that appears reasonable in effect may be assumed to have been adequately supported at the time it was made. Reconstruction reverses that assumption by asking a narrower question: what evidence actually existed at the decision moment, regardless of what followed.
By decoupling evidential sufficiency from outcome, reconstruction avoids both outcome bias and retrospective rationalisation.
5.2 Evidence Absence as a Positive Finding
In conventional review, absence is difficult to articulate. A reviewer may sense that something is missing without being able to specify it precisely. Systematic reconstruction transforms absence into a positive analytical finding.
By testing for the presence, completeness, and decision-grade status of evidence topic by topic, reconstruction allows the analyst to say not merely that evidence is unclear, but that specific categories of evidence demonstrably did not exist at the point of determination.
This shift—from intuition to explicit classification—is one of the principal advantages of reconstruction-based analysis.
5.3 Consistent Treatment of Lawful Deferral
Reconstruction makes it possible to apply a consistent test to claims of lawful deferral.
Rather than accepting deferral implicitly, reconstruction requires explicit answers to three questions:
- Is the topic decision-critical at the relevant stage?
- Is deferral permitted by policy or law for that topic?
- What evidence exists at decision stage to justify reliance on deferral?
Where these questions cannot be answered on the decision record, reconstruction identifies the issue as one of evidential sufficiency rather than planning judgement.
5.4 Visibility of Cross-Case Patterns
Perhaps most importantly, systematic reconstruction enables comparison across decisions.
When evidential sufficiency is assessed using consistent criteria, patterns become visible that are not apparent when cases are considered individually. Similar failure modes can be identified across unrelated decisions, even where those decisions differ in scale, location, or outcome.
This pattern visibility does not arise from aggregation of complaints or appeals, but from the repeatable application of the same analytical test to multiple decision records.
5.5 Reduction of Interpretive Drift
Reconstruction constrains interpretive drift by anchoring analysis to a fixed evidential state.
Without reconstruction, interpretation may drift over time as additional information becomes available, assumptions are retrospectively filled in, or later compliance is treated as evidence of earlier sufficiency.
Systematic reconstruction arrests this drift by treating the decision moment as immutable. Evidence either existed then, or it did not.
5.6 Increased Reconstructability and Transparency
A reconstructed decision record is, by definition, more transparent. It allows third parties—whether reviewers, auditors, or decision-makers themselves—to see clearly:
- what was relied upon;
- what was assumed;
- what was deferred; and
- what was absent.
This transparency does not imply fault. It improves the ability to explain decisions accurately and consistently, which is valuable regardless of whether a decision is challenged.
5.7 Implication
Once systematic reconstruction is applied, decision-stage evidential sufficiency becomes observable rather than speculative. What previously depended on professional intuition or prolonged manual review becomes explicit, structured, and repeatable.
The implication is not that all decisions will be found wanting, but that the conditions under which evidential sufficiency can be confidently demonstrated become clearer. Where sufficiency exists, reconstruction strengthens confidence. Where it does not, the nature of the gap can be described precisely.
6. From Method to Implementation
The analytical approach described in the preceding sections demonstrates that decision-stage evidential sufficiency can be tested systematically, provided that reconstruction of the decision record is treated as a first-class task. The remaining question is therefore not whether such reconstruction is conceptually possible, but whether it can be carried out reliably, consistently, and at scale.
Historically, this form of reconstruction has been undertaken manually. It relies on professional expertise, sustained attention, and extensive cross-referencing of dispersed documentation. While effective in individual cases, manual reconstruction is time-intensive, difficult to replicate, and inherently fragile. Its success depends heavily on the skill and persistence of the individual reviewer, and it does not readily support cross-case comparison.
Recent developments in structured text analysis, classification, and rule-based assessment make it possible to operationalise the reconstruction process described in this paper. By encoding the analytical tests of decision-stage evidential sufficiency—existence, completeness, lawful deferral, and reconstructability—into a consistent framework, reconstruction can be performed repeatably without reliance on interpretive intuition alone.
One such implementation is the Planning Governance Assessment Tool (PGAT). PGAT operationalises the reconstruction method described in this paper by treating planning determinations as discrete decision events and systematically analysing the evidential state that existed at the point of determination. It does not assess planning merits, substitute professional judgement, or predict outcomes. Its function is limited to identifying whether decision-grade evidence existed, how unresolved matters were treated, and whether the decision record can be reconstructed in a manner consistent with principles of procedural fairness.
PGAT’s purpose is not to replace professional review, but to stabilise it. By compressing reconstruction into a structured, repeatable process, it reduces reliance on memory, narrative assurance, and post hoc interpretation. This allows reviewers to focus on substantive issues rather than the mechanics of evidential discovery.
Importantly, PGAT is not presented here as the only possible implementation of systematic reconstruction. It is cited as evidence that the method described in this paper is tractable and can be implemented in practice. The existence of such an implementation demonstrates that decision-stage evidential sufficiency is not an abstract ideal, but an observable property of decision records that can be tested directly.
The broader implication is that once reconstruction is treated as an analytical discipline rather than an ad hoc exercise, questions of evidential sufficiency move from the realm of intuition to that of method. Whether implemented through PGAT or other future tools, systematic reconstruction enables clearer explanation of decisions, more consistent review, and improved transparency—without presupposing error or prescribing outcomes.
Executive Summary
Planning decisions rely on the assessment of complex, distributed, and technical evidence. In practice, the scale and dispersion of this material make full reconstruction of the decision-stage evidential record difficult, time-consuming, and uncommon. As a result, evidential sufficiency is often presumed rather than verified.
This paper describes this mechanism succinctly: complexity breeds presumption. Where verification is impractical, confidence in process substitutes for reconstruction of evidence.
The paper examines decision-stage evidential sufficiency as a distinct analytical concept, focusing not on planning outcomes or professional competence, but on whether the evidence necessary to assess material considerations demonstrably existed at the moment decisions were taken. It identifies recurring failure modes by which evidential insufficiency can arise without being immediately apparent, and explains why conventional professional review processes are not designed to detect these patterns reliably.
The paper then shows that this limitation is structural rather than individual. Existing review practices are oriented toward outcomes, reasonableness, and arguability, rather than systematic reconstruction of the evidential state at a fixed decision point. In the absence of a formal reconstruction method, evidential absence is difficult to identify and patterns across decisions remain obscured.
Finally, the paper demonstrates that this condition is not inevitable. Systematic reconstruction of the decision-stage evidential record makes it possible to separate outcome from evidential state, treat absence as a positive analytical finding, and identify repeatable patterns across cases. What was previously impractical becomes achievable.
One implementation of this reconstruction approach is the Planning Governance Assessment Tool (PGAT), which operationalises the analytical methods described. Its significance lies not in the tool itself, but in what it demonstrates: that decision-stage evidential sufficiency is an observable, testable property of decision records rather than a matter of presumption.