The research, conducted by Alexis Lalevée and Claudine Gillot in collaboration with an engineering company specializing in complex infrastructure, analyzed ten value engineering projects carried out between 2013 and 2020. These are the kinds of projects that shape the lives of multiple generations: transport and energy systems with time horizons approaching a century. The team collected end-of-study reports from each project and classified every value criterion into four dimensions: technical, economic, social and ecological. Two independent coders performed the classification, one a researcher working from the written reports and the other a value engineering expert who had firsthand knowledge of the projects and the intentions of their stakeholders. Disagreements between the two coders were resolved through discussion, and the expert’s industrial classification was ultimately retained to ensure alignment with actual practice.

The numbers are striking. Of the 88 value criteria identified across the ten projects, 45 percent were primarily technical or functional, and 32 percent were economic. In other words, 78 percent of the criteria that determined what counted as valuable in these multi-generational infrastructure projects served technical and economic ends. Ecological criteria accounted for just 7 percent of the total, and social criteria for 16 percent. The imbalance varied widely between projects: in one project, only a single criterion out of eleven escaped the techno-economic mold, while in another, only two out of fifteen criteria were techno-economic. Nuclear projects proved especially skewed, with technical criteria making up nearly 66 percent of their value criteria and ecological criteria a mere 2.63 percent.

To understand how this imbalance arises, the researchers traced the value engineering process as it unfolds in practice, using a well-documented illustration case about connecting two cities. The method begins with stakeholder identification, in which the funding authority assembles a working group of roughly fifteen parties, including citizens and companies. Individual interviews then characterize stakeholder needs, which are translated into value criteria, some easily quantified and others harder to express. Functional analysis follows, ranking the project’s functions by importance; in the illustration case, passenger transport accounted for 45 percent of the project’s importance and limiting journey times another 25 percent. Potential solutions, from railways and roads to canals and cycle routes, are then explored, filtered through five types of feasibility, and compared against the defined value criteria before a report goes to the decision-maker.

The problem, the study argues, lies in the method’s deep functional bias. Value engineering defines value as a relationship between functions and resources, and its functional analysis translates needs into functions described as transformations of energy within a system. Sustainability concerns get absorbed into this machinery only by being converted into functions themselves. There is no such thing as a biodiversity value criterion in the literature; instead, there is a function of protecting biodiversity. Environmental integration typically happens through Life Cycle Assessment, the industry’s dominant tool for measuring ecological impact, which shares the same functional logic. The researchers contend that this translation may oversimplify complex socio-ecological systems and that treating ecology as something made useful through functional units is itself a debatable assumption in an era of planetary resource depletion.

A second limitation is subjectivity. Value criteria are co-constructed in workshops where stakeholders with different expertise, hierarchical positions and interests negotiate what matters. The word safety means one thing in the railway sector, where it aligns with common-sense notions of security, and something quite different in the nuclear sector, where it refers to the integrity of goods and people to ensure continuity of operations, while security covers external risks like intrusion. Criteria such as image and awareness, modularity of the installation, or circular economy blur across social, economic and technical dimensions depending on who is defining them. Unlike formal multi-criteria decision-making methods such as the Analytic Hierarchy Process or MACBETH, which provide structured protocols for weighting criteria through pairwise comparisons, value engineering has no standardized method for resolving conflicts or ensuring consistency. Stakeholders with technical or economic expertise may simply prioritize the dimensions they know best, quietly marginalizing social and ecological concerns.

The researchers found a telling exception that points toward a remedy. In one project, stakeholders were given the opportunity to articulate their individual perspectives before a collective consensus was established, and that same project showed a notably higher integration of sustainability issues. This correlation, the authors suggest, hints that preserving the individual dimension within collective value construction could be key to broadening what counts as valuable. It also raises a deeper question about whether the very notion of a shared collective value erases individual concerns that are essential for capturing socio-ecological issues, a phenomenon documented in social psychology research on group processes.

The study also identifies a cognitive barrier. Social and ecological issues remain abstract concepts for most stakeholders, who lack the knowledge and skills to characterize and measure them within a framework that, by definition and by habit, carries technical and economic connotations. The authors propose that frameworks like the Doughnut model, which visualizes a safe and just operating space between social foundations and ecological ceilings, could help stakeholders build the understanding needed to define genuinely sustainable value criteria. Previous work by the lead author has explored adapting the Doughnut for engineering training, though the researchers caution that such theoretical proposals remain untested in real-world industrial applications.

The authors are candid about the limits of their own study. The analysis focused exclusively on early design phases, when solutions are still unclear, so the findings may not generalize to later project stages where sustainability criteria could evolve or gain significance. The research relied on a single value engineering expert for project selection and final classification validation, introducing potential selection and classification bias, although the elements in the project reports themselves suggested the techno-economic dominance observed. The underlying project data were confidential and had to be anonymized, with only generic criterion terms like modularity, safety and cost available for discussion. The authors recommend repeating the experiment with multiple experts from diverse backgrounds, including environmental and social scientists, and integrating structured multi-criteria methods to standardize criteria weighting.

The takeaway for the infrastructure sector is that value engineering, for all its adaptability and its genuine strength in bringing stakeholders together, cannot be relied upon to deliver sustainability on its own. The method’s functional bias, its unstructured subjectivity and the absence of any common reference framework for defining sustainable criteria combine to push socio-environmental concerns to the margins of early design decisions, the very decisions that shape a project’s impact for a century. The researchers argue that hybrid approaches, combining the collaborative power of value engineering workshops with the formal weighting techniques of multi-criteria decision-making, could rebalance the scales. Testing such approaches in industrial settings, they conclude, is the necessary next step if the tools that design our railways and power plants are to serve not just budgets and technical performance, but the societies and ecosystems that must live with the results.

Subject of Research: Limits of value engineering assessment criteria for integrating sustainability in early design phases of major infrastructure projects

Article Title: The limits of value engineering assessment criteria for integrating sustainability issues – Lessons from early design phases of major civil engineering infrastructure projects

Article References: Lalevée, A., & Gillot, C. (2026). The limits of value engineering assessment criteria for integrating sustainability issues – Lessons from early design phases of major civil engineering infrastructure projects. Environmental and Sustainability Indicators, 32, Article 101547. https://doi.org/10.1016/j.indic.2026.101547

Image Credits: AI Generated

DOI: 10.1016/j.indic.2026.101547

Keywords: value engineering, sustainability, infrastructure design, life cycle assessment, multi-criteria decision-making, stakeholders, railway, nuclear, functional analysis, value criteria, Doughnut model, early design phases

The study, conducted by Nathan Bunyan, Clarissa Feuerer, and Athanasios Vostanis of the Tizard Centre at the University of Kent, was pre-registered on PROSPERO and followed PRISMA reporting guidelines. The team searched seven databases, hand-searched thirteen behavior-analytic journals, contacted key authors, and combed grey literature in the form of dissertations. After screening more than thirteen thousand records, they identified thirty studies, twenty-seven published and three unpublished, representing 111 individual applications of SBT across 107 participants. That scale matters, because until now only a single scoping review had examined SBT itself, and it reported no formal effect sizes and no assessment of study quality or risk of bias.

To understand what the reviewers were evaluating, it helps to know how SBT works. The intervention package rests on two pillars. The first is functional communication training, one of the most extensively researched behavioral interventions, in which a child is taught an alternative communication response that serves the same function as the challenging behavior, such as requesting a break or asking for attention. The second pillar is delay and denial tolerance training. Because the new communication response is initially reinforced every single time, the reinforcement schedule must gradually be thinned so the skill can survive in the real world, where requests are sometimes refused or delayed. In SBT, this thinning is contingency-based: children are asked to engage in meaningful tasks or activities during the delay period before earning reinforcement, an approach research suggests produces better tolerance and lower rates of problem behavior than simply making children wait.

Before treatment begins, practitioners conduct a functional analysis to identify the environmental events that evoke and reinforce the challenging behavior. Most SBT implementations in the reviewed literature relied on a variant called the interview-informed synthesized contingency analysis, in which caregivers are interviewed openly and the resulting contingencies, often combinations such as escape from demands paired with access to preferred items, are tested together in a single synthesized condition. In the treatment phase, many applications taught an omnibus communication response, a single phrase such as “my way” that accesses all identified reinforcers, before progressively shaping more complex requests. A specific tolerance response, such as taking a breath and saying “okay,” is then trained to help children cope with denial of reinforcement without relapsing into problem behavior.

The meta-analysis quantified outcomes using Baseline-Corrected Tau, a non-overlap effect size metric that adjusts for baseline trends and aligns well with visual analysis of single-case data. Across the 59 participants for whom values could be computed, the mean Tau-BC was 0.47, falling squarely in the moderate range, with individual values spanning from minus 0.35 to a perfect 1.00. Twenty-five participants showed moderate change, fifteen showed large change, and eight showed very large change, while eleven showed only small change. The reviewers caution, however, that forty-two participants had wide 95 percent confidence intervals, indicating substantial uncertainty around many of the estimates. When the analysis was restricted to participants without wide intervals, the picture brightened considerably: eight very large changes, two large, six moderate, and just one small.

Quality assessment told a less flattering story. Using the Evaluative Method, the reviewers rated only two studies as borderline-strong and four as adequate, while thirteen were borderline-adequate and eleven were weak. In the abstract’s summary figures, 37 percent of the literature scored weak and just 7 percent reached borderline-strong. An evidence-based practice Z score of 46, calculated from the six studies rated adequate or above, suggests SBT qualifies as a probable evidence-based practice on paper. Yet the authors urge caution. They note that the Evaluative Method can be overly sensitive, penalizing studies that publish unflattering data from some participants, which may actually indicate a lower-risk design such as a consecutive case series. The risk of bias tool flagged further concerns: every study was rated high risk for blinding of participants, personnel, and outcome assessors, and in half the studies participants received pre-session teaching that inflated the apparent immediacy of treatment effects.

One clear strength of the SBT literature is its attention to social validity. Twenty-three of the thirty studies, covering 73 percent of participants, reported social validity data, almost always via questionnaires completed by caregivers, home care teams, or school staff. Wherever procedures and outcomes were rated, responses were positive, and two individuals who received the treatment themselves also reported positive experiences. Some studies went further, involving parents in goal setting, allowing parents to observe or terminate sessions at will, and letting children choose whether to participate. Notably, parents given the option to end sessions chose not to. Still, the reviewers point out that social validity was rarely measured from the perspective of the children receiving treatment, and they call for qualitative research with autistic adults, parents, and recipients of support to broaden the evidence base.

The review also exposes striking gaps in who has been studied and where. Around three-quarters of participants were male, 96 percent were under fourteen years old, and 80 percent were autistic, with most able to speak in full sentences or multi-word phrases. Only two participants were over eighteen. Nearly all studies originated in the United States, most were conducted in outpatient clinics by therapists, graduate students, or board-certified behavior analysts, and most research teams were connected to the originators of the approach, with only eleven studies coming from independent groups. Vocal verbal communication dominated both the initial and terminal communication responses, with aided augmentative and alternative communication appearing in roughly a fifth of cases and unaided AAC almost never. For practitioners hoping to apply SBT in schools, homes, or with minimally verbal individuals, the reviewers warn that procedures may need adaptation, timelines may differ, and effectiveness is not yet guaranteed outside the well-studied profile.

Practical details emerged that will interest clinicians and families weighing the costs of care. Where data were available, treatment averaged 68.78 total hours, with a range of 23 to 167 hours, and an average estimated cost of just under 6,000 dollars, suggesting SBT may be comparatively cost-effective. Most applications allocated fewer than twenty hours per week. Implementers also adapted procedures in ways that appear to reduce distress: some achieved reductions in challenging behavior without extinction at all, others applied extinction only to less dangerous behavior or used differential reinforcement, and the majority reinforced precursors or milder forms of problem behavior. These choices align with growing movements toward trauma-assumed, assent-based, and compassionate care in behavior analysis, though the reviewers note that some schedule-thinning practices, such as resetting reinforcement criteria, could still be experienced as aversive and deserve closer study.

The authors’ bottom line is measured rather than triumphant. SBT emerges as an emerging, potentially evidence-based practice with moderate average effects, strong stakeholder endorsement, and a flexible structure that clinicians individualize extensively. But with most studies rated weak, blinding absent across the board, and the evidence concentrated in a narrow slice of the population, the field needs higher-quality, independently conducted research in more diverse settings before confident, widespread recommendations can be made. The reviewers recommend concrete fixes: clearer operational definitions, reported inclusion criteria, demographic transparency, fidelity measurement, consideration of blinding, maintenance and generalization testing, and including pre-session teaching data in outcome measurement. For now, they advise practitioners to treat SBT as a general template, weighing the evidence for a particular population or context and tailoring the intervention to each individual’s needs and preferences, rather than as a one-size-fits-all prescription.

Subject of Research: Systematic review and meta-analysis of skill-based treatment for challenging behavior in autism and developmental disabilities

Article Title: Evaluating the Effects of Skill-Based Treatment: A Systematic Review and Meta-Analysis of Single-Case Studies

Article References: Bunyan, N., Feuerer, C., & Vostanis, A. (2026). Evaluating the Effects of Skill-Based Treatment: A Systematic Review and Meta-Analysis of Single-Case Studies. Journal of Autism and Developmental Disorders. https://doi.org/10.1007/s10803-026-07547-2

Image Credits: AI Generated

DOI: 10.1007/s10803-026-07547-2

Keywords: skill-based treatment, challenging behavior, autism, functional communication training, meta-analysis, single-case design, schedule thinning, functional analysis, social validity, evidence-based practice, behavior analysis, Tau-BC