Critical Systems Heuristics

• Critical Systems Heuristics is a framework that uses twelve canonical questions to uncover and articulate normative boundary judgments in system design.
• It contrasts current practices ('is') with ideal standards ('ought') to reveal implicit values, exclusions, and stakeholder biases.
• Its application in smart cities and requirements engineering highlights the need for iterative, inclusive design to enhance ethical and sustainable outcomes.

Critical Systems Heuristics (CSH) is a methodological framework within Critical Systems Thinking (CST) that structures systemic inquiry around the explicit examination and contestation of boundary judgments. CSH posits that all system design and intervention processes are unavoidably shaped by normative choices that define what is included, excluded, prioritized, or marginalized—choices that reflect the interests, epistemologies, and power relations of designers and stakeholders. Rather than seeking a single optimal solution or a complete correspondence with reality, CSH applies a set of twelve canonical boundary questions organized in four dimensions (Beneficiary/Motivation, Actor/Power, Expert/Knowledge, Legitimation/Witness) to prompt a cycle of reflexive critique. These questions distinguish "is" (what currently prevails) from "ought" (what should hold in a fully justified design), making the underlying value systems and stakeholder exclusions explicit and revisable. CSH has been applied to domains such as smart city planning (McCord et al., 2019) and requirements engineering (Duboc et al., 2019), where it systematically foregrounds questions of justice, emancipation, and genuine sustainability.

1. Theoretical Foundations and Epistemological Commitments

CSH is rooted in the broader tradition of Critical Systems Thinking, differentiating itself from modeling-based or optimization systems approaches through its critical intent and reflexive epistemology. It rejects a naive correspondence theory of truth, treating system models as discursive artifacts situated within reference systems of values and assumptions. Every system description, in this view, rests on boundary judgments—decisions about who counts as a stakeholder, what constitutes success, whose expertise is credible, and what constraints are treated as exogenous. These judgments are understood as inherently partial, contestable, and consequential for justice and inclusion.

CSH aims not only to represent but to critique system configurations, exposing how certain groups benefit, others are silenced, and unasked alternatives persist. Its explicit goal is to erode distinctions between "involved" actors (such as planners, experts, sponsors) and "affected" populations (such as residents, users, citizens) (McCord et al., 2019). The framework is operationalized via twelve non-numerical questions serving as heuristics for structured reflection and debate, challenging assumptions that otherwise remain implicit.

2. CSH Boundary Questions: Schema and Application

The twelve boundary questions of CSH—each articulated in "is" and "ought" form—are grouped into four intersecting categories. These categories correspond to the primary concerns of system critique: motivation, control, knowledge, and legitimization. The canonical schema is presented below (LaTeX-ready format):

\begin{table}[h] \centering \caption{CSH categories and boundary questions} \begin{tabular}{|l|p{0.75\linewidth}|} \hline \bfseries Category & \bfseries Boundary questions \ \hline Client / Beneficiary & 1. Who is (ought to be) the client or beneficiary? \ & 2. What is (ought to be) the purpose? \ & 3. What is (ought to be) the measure of improvement (success)? \ \hline Actor / Power (Control) & 4. Who is (ought to be) the decision-maker or controller of resources? \ & 5. What resources are (ought to be) under their control? \ & 6. What is (ought to be) outside their control (the environment)? \ \hline Expert / Knowledge & 7. Who is (ought to be) the relevant expert or knowledge source? \ & 8. What knowledges or skills are (ought to be) necessary? \ & 9. What guarantees or assures successful implementation? \ \hline Legitimation / Witness & 10. Who is (ought to be) the witness of those affected but not involved? \ & 11. What opportunities are (ought to be) available for those affected to emancipate themselves from the planner’s worldview? \ & 12. What space is (ought to be) available for reconciling different worldviews? \ \hline \end{tabular} \end{table}

Each question is designed to surface boundary judgments at the point of system intervention, facilitating further contestation and revision in collective forums.

3. Reflexive Application: Case Studies in Smart City and Requirements Engineering

In "Sidewalk and Toronto: Critical Systems Heuristics and the Smart City," McCord and Becker apply the CSH schema to analyze the planning documents and engagement processes of the Sidewalk Toronto project (McCord et al., 2019). They reconstruct both official ("is") answers—derived from RFPs, vision documents, and project agreements—and critically contrast these with what "ought" to be endorsed from an emancipatory and justice-oriented viewpoint.

For example, the official beneficiaries include prospective residents, businesses, public authorities, and the corporate actor Sidewalk Labs, justified by reference to a "triple bottom line" rhetoric. CSH critique demonstrated that profit-maximization dominates, affordable housing is operationalized through market-rate definitions that marginalize low-income renters, and resident voices are structurally excluded from decision-making. Similarly, claims of environmental sustainability are reframed as services to be optimized through proprietary data platforms rather than community-driven ecological practices.

In requirements engineering, Duboc et al. employ CSH during iterative stages of the HomeSound system specification (Duboc et al., 2019). CSH-informed stakeholder interviews and reflections exposed blind spots: family members, though unrecognized in early documents, emerged as key secondary beneficiaries; privacy concerns led to hardware and software constraints not present in initial technical requirements. The process produced an "^^^^10^^^^" distinguishing "is" from "ought" for each boundary category. The mapping between CSH categories and Volere specification sections served as a pragmatic bridge to standard RE documentation.

Table: Examples of CSH Application in HomeSound Requirements Engineering

Category	CSH Question (Is/Ought)	Observed Impact on Requirements
Beneficiaries	Is: Who benefits? Ought: Who should benefit?	Families added as secondary beneficiaries; notification interfaces
Purpose	Is: What is the system’s purpose? Ought: Ethical function?	Purpose redefined to include "self-determination"
Measures of Success	Is: What indicators? Ought: Valid assessment?	Integration of clinical scales (Zarit, anxiety) for success reporting
Decision Makers	Is: Who makes decisions? Ought: Who should?	Multi-party sign-off (users, families, security auditors)
Resources	Is: Control over hardware/software? Ought: Requirements?	Penetration tests, secure communication channels, hardware tamper detection
Environment	Is: Constraints? Ought: What privacy is owed?	Mic must be off except in alarms; local data preprocessing

4. Marginalization, Emancipation, and Boundary Critique

CSH exposes the mechanisms by which marginalization and constrained emancipation manifest in system design and governance. In the Sidewalk Toronto case, McCord & Becker’s analysis highlighted that top-down, scripted public engagement models decouple “co-design” from true agenda-setting by residents. Boundary devices such as the Civic Data Trust are presented as emancipatory propositions but, under scrutiny, reveal nonpublic governance structures and proprietary control over core digital assets. Public hearings and witness activities are mediated, often excluding critical voices and grassroots organizations from meaningful participation (McCord et al., 2019).

The HomeSound case further demonstrated how boundary critique can affect system specification: marginalized groups (elderly with cognitive decline) were systematically underconsulted until late phases, and translation from philosophical critique to actionable requirements demanded a bridging role for the engineer (Duboc et al., 2019). This suggests that even robust CSH application is susceptible to practical limits in representation and actionable scope.

5. Conceptual Cycle and Boundary Negotiation

CSH operationalizes systemic boundary critique as a reflexive cycle among four primary dimensions (Beneficiary, Actor, Expert, Legitimation), with each category’s judgments recursively presupposing the others. The adapted diagram from Ulrich, rendered in LaTeX/TikZ notation, schematizes this as follows:

\begin{figure}[h] \centering \begin{tikzpicture}[node distance=2cm, every node/.style={draw, rounded corners, align=center}] \node (C) {Client / Beneficiary}; \node[right=of C] (A) {Actor / Power}; \node[below=of A] (E) {Expert / Knowledge}; \node[left=of E] (L) {Legitimation / Witness}; \draw[->] (C) -- (A) node[midway, above] {Who controls?}; \draw[->] (A) -- (E) node[midway, right] {Who knows?}; \draw[->] (E) -- (L) node[midway, below] {Who speaks?}; \draw[->] (L) -- (C) node[midway, left] {Who benefits?}; \end{tikzpicture} \caption{CSH boundary-critique cycle (adapted).} \end{figure}

This cyclic structure mandates that boundary judgments be revisited iteratively to produce a defensible and transparent system specification. Practitioners are counseled to use ideal map templates and mapping tables for repeatable documentation.

6. Integration in ICT for Sustainability and Systems Design Practice

CSH has demonstrated value in ICT for Sustainability (ICT4S) and requirements engineering by making explicit the latent value judgments within design and planning processes. Its capacity to uncover how sustainability and innovation are rhetorically mobilized, often to privilege corporate profit or technical solutionism over communal interests, positions CSH as a uniquely powerful evaluation and design tool (McCord et al., 2019).

As an evaluative lens, CSH can be used in post-hoc critique to reveal exclusions and contestable boundary settings; as a design aid, it facilitates boundary negotiation prior to system implementation. In practice, successful integration with specification frameworks (Volere, IEEE 830) requires careful mapping and explicit rationale sections distinguishing "is" from "ought." Recommendations include using CSH questions alongside standard checklists, maintaining living ideal maps, and incrementally expanding scope to remedy identified blind spots (Duboc et al., 2019).

A plausible implication is that widespread CSH adoption could measurably increase the ethical robustness, social validity, and inclusiveness of technical system interventions in complex sociotechnical contexts. However, the process remains labor-intensive and contingent on the ability to bridge philosophical boundary critique with actionable system requirements, particularly for marginalized or hard-to-reach user groups.