From Expert Evaluation to Instrumented Measurement

Introduction

The SBNFA™ framework draws on documented phenomena and translates them into a constructed grid. A first application, by multi-criteria analysis, has been carried out (benchmark of six dynamic seats, Chapter 4); validation of the model remains open. This fifth chapter describes the next step: Level 2, which aims to quantify the variables objectively and test the reproducibility of ratings.

[OUTLOOK] Instrumental testing must be able to challenge the relevance of the functions and variables, their boundaries and their anchors, as much as their correspondence with measurements. It tests an SBNFA construct, without conflating this validation with that of the phenomena already documented.

This is also the chapter that answers the question put to any company that publishes a benchmark including its own product: how is this work anything other than a sales argument? The answer rests on three elements: criteria grounded in knowledge independent of Aporia®, declared limitations, and avenues for discussion and measurement open to third parties.

1. From Scientific Foundation to Instrumental Testing

The framework follows a classic scientific path, and each step has its own stage of completion.

2. Two Levels of Evaluation

The framework is designed for two successive levels of use, without altering its functional logic [1].

In both cases, the framework remains independent of the technical solutions evaluated. A Level 1 evaluation is not an approximate version of Level 2: it serves a different purpose, which is to structure the questions, identify the capabilities to be measured and compare architectures before the budget for an instrumented protocol is committed.

3. What Level 1 Can and Cannot Do

Level 1 evaluation relies on observing architectures and how they function, using a grid, criteria and conditions identical for all devices. It produces profiles, not measurements.

4. Toward Level 2: Measurement Avenues by Variable

The framework specifies that each variable will be associated with a measurement method, a unit and a protocol. The indicators it adopts to objectively establish the state of a variable — range, threshold, dead zone, hysteresis, left/right independence, continuity of response, pressure mapping, residual displacement — carry no score of their own: they serve to document the observed state [1].

The following table suggests, as avenues to explore, the family of measurements that could correspond to each group of variables. [OUTLOOK] This is not a finalized protocol: each avenue has yet to be turned into a protocol.

Instrumented studies already exist on related quantities: muscle activation, physical activity and posture when using dynamic chairs [2], lumbar activation and posture on an unstable surface [3], and intradiscal pressure in standing and sitting [4]. Movement variability is the subject of nonlinear analysis methods [5]. These studies show that the protocols exist, and they will serve as methodological references.

5. Proposed Instrumental Program and Implementation Conditions

[OUTLOOK] Measurements are planned with a university biomechanics laboratory starting in 2027.

Before the study, the following must be specified: the devices and settings, the population or mechanical setup, the loading conditions, the repetition of trials, the quantities and units, calibration, uncertainty, the analysis strategy and the criteria for conclusions. Mechanical measurements, sensorimotor observations and biological responses require separate protocols.

Evaluators will need explicit anchors and comparable records. A measurement validates a variable only if the correspondence between the definition, the observable and the measured quantity is justified. Contradictory or inconclusive results must remain visible.

6. What Level 2 Will Make It Possible to Verify

Level 2 addresses specific questions, which concern objective quantification rather than the discovery of a foundation.

7. Limitations of Level 1 and the Responses Provided

Level 1 has its own limitations, which explain the role of Level 2.

8. An Evidence Scale for Situating Each Claim

To situate a claim, one need only know which rung of an evidence scale it rests on.

9. Scientific Discussion and Application by Third Parties

The framework is designed to be applied by a third party: its criteria are independent of the solutions evaluated, each variable has its anchors, each score must be justified, and so must the rejection of the higher state.

Four types of contribution are possible, and useful:

• challenging a score: showing, through observation or measurement, that a higher or lower state is or is not fully demonstrated;
• refining a variable: proposing a more precise definition, anchor or boundary rule;
• expanding the sources: contributing studies that better document a foundation or its application to seating;
• applying the grid to another device: this is the best way to test its discriminant capacity and technological neutrality.

The framework stipulates that any change to a monograph is carried over into the summary documents, the radar chart and the consolidation workbook, so that a correction leaves no inconsistency behind [6]. Blue Portance welcomes well-argued contributions.

The distinction between a method audit and a product-doctrine audit described in Chapter 1 applies here: conclusions about a product and conclusions about the model must be argued separately. A product observation may nonetheless reveal a methodological weakness and lead to an explicit revision of the framework.

10. Outlook

[OUTLOOK] The next steps test the SBNFA construct against independent observations and measurements.

• Consider extending the sample to other families of seating, including static and synchronous chairs, without changing the functional logic of the framework.
• Confirm partners and timeline, finalize a protocol, then test each variable against the measured quantities.
• Extend application of the grid to third-party evaluators and test the reproducibility of ratings.
• Revise the framework through dated versions as measurements refine the anchors.

The framework is also designed to evaluate other technologies: Aporia® is only its first application. A future device from another manufacturer that offers capabilities described by the grid will be rated in the same way.

Chapter 6 (dynamic seating glossary and bibliography) brings together the glossary, the index of the nineteen variables and the annotated bibliography, specifying for each source its contribution and its scope within the framework.