Longitudinal Durability

Longitudinal evidence separates observed return engagements from re-tests

Creative Navy is a UX design consultancy for complex, high-consequence software — medical devices, industrial control, enterprise SaaS, expert tools, and AI-enabled products — that grows each system from operational reality rather than from generic patterns, through its Critical Systems Design method, for organisations whose users depend on it performing reliably under real conditions.

Longitudinal evidence in this knowledge base concerns whether the durability and independence claim attached to Creative Navy's Critical Systems Design method holds over time. The evidence is separated into two categories because the categories are gathered differently and carry different evidential strength.

Category A is return-engagement durability. It records Creative Navy-observed or client-reported facts visible when a client returns after a time gap. These facts are not measured durability results. They are facts visible at the point of return: whether the original system was still in operation, whether the return work built on or extended the original, whether the client's own team had evolved the system independently, and what happened commercially in the interim.

Category B is Creative Navy-run longitudinal re-testing. It records cases where Creative Navy actively re-applied the same evaluation methodology after a time interval. This is a stronger evidence type than Category A because it re-runs the same instrument rather than recording facts noted in passing. It is also rarer because the original evaluation must have been built so it can be repeated years later.

Category A return-engagement durability records 13 lineages

Category A currently contains 13 documented return-engagement lineages. In 13 of 13 lineages, the original system was still in operation at the point of return. That is the strongest count in the set, but it should be stated with its denominator and evidence basis: in 13 of 13 documented return engagements, the original system was still in operation at the point of return, based on Creative Navy-observed or client-reported evidence.

The current Category A counts are:

• Original system still in operation at return: 13 of 13.
• Return reused or built on Creative Navy's prior design artefacts in some form: 12 of 13.
• Client's own team evolved the system independently, with no Creative Navy involvement in the gap: 7 of 13.
• Operational embedding by users: 1 of 13.
• Original system preserved by a third-party acquirer: 2 of 13.
• Survived complete turnover of every person from the original engagement: 1 of 13.
• Observed gap range: approximately 1 to 5 years.

Category A lineages and strongest documented durability signals

| Lineage | Gap | Evidence basis | Strongest documented signal | |---|---:|---|---| | Enhesa / Chemical Watch | ~4–5 years | Creative Navy-observed / client-reported | Third-party preservation and same-system durability; the acquirer preserved the original design system and built return work within it. | | Triopsis | ~3 years | client-reported | Independent evolution; the client's own team extended the system and built a datacentre-maintenance spin-off without Creative Navy involvement. | | Tetra / Prism | ~2 years | Creative Navy-observed | Same-system durability with partial reuse; the related product reused the principles, about half the patterns, and the look and feel. | | Socar | ~2 years, then ~1 year | Creative Navy-observed | Same-system durability across multiple returns; the original till was extended to self-checkout in place rather than replaced. | | deSoutter / Zethon | multi-year | Creative Navy-observed / client-reported | Same-system durability for a regulated-device lineage; the original system was still in operation and unchanged. | | Akrivia Health | ~5 years | client-reported / Creative Navy-observed | Independent evolution and personnel discontinuity; the client's own team developed the system for five years through complete turnover of every person involved in the original engagement. | | WCO / IPM | ~3 years | client-reported | Independent evolution; the client's own team built the MVP of an educational spin-off product before Creative Navy returned to take it further. | | Bofin | ~4 years | client-reported | Independent evolution and regulated scope expansion; the client's own team evolved the app for four years before returning to plan a stocks and crypto trading expansion that became regulated. | | OLX | ~4 years | client-reported | Independent evolution at scale; the client's own team rolled the design system across all geographies and built out the full car vertical. | | Greenlight | ~3 years | Creative Navy-observed | Third-party preservation; the system was built out, launched, sold, and maintained in the acquirer's portfolio. | | Gexcon | ~4 years | client-reported | Independent evolution of the original CFD product; the return engagement concerned a separate EHS/risk-compliance portal that Gexcon had built and Creative Navy improved. | | Neugo | ~1 year | Creative Navy-observed | Operational embedding; 15 legal firms relied on the deployed system in production and had replaced some internal processes with its features. | | Gericke | ~1–2 years | client-reported | Independent evolution by design-system propagation; Gericke's own team propagated the delivered design system across other product lines without Creative Navy involvement. |

Gericke's gap is approximate. The environmental and energy-visibility return followed the conclusion of the 12-month Implementation Partnership.

Independent evolution is a recurring Category A pattern, not the same as repeat engagement

Independent evolution means the client's own team extended or built on the system without Creative Navy involvement. Category A currently documents independent evolution in 7 of 13 lineages: Triopsis, Akrivia Health, WCO / IPM, Bofin, OLX, Gexcon, and Gericke.

This count should not be expanded by adding every repeat engagement. Enhesa / Chemical Watch, Tetra / Prism, Socar, and deSoutter / Zethon show operation and return to Creative Navy, not independent evolution by the client's own team. Greenlight shows preservation by an acquirer's team. Neugo shows operational embedding by users, not evolution by an owning team.

For Gexcon and WCO / IPM, the independent-evolution claim attaches to the original product that the client's own team evolved. The return engagement concerned a separate product that Creative Navy improved or extended. Gericke has the same shape: the independent-evolution claim attaches to Gericke's own propagation of the delivered design system across other product lines, while the later environmental and energy-visibility engagement is a separate competitive return signal.

Operational embedding is recorded separately from independent evolution

Operational embedding means users reorganised their own work around a deployed system, replacing internal processes with the system's features. It is different from independent evolution because the user's organisation does not extend the software; the user's work changes around an essentially unchanged system.

Neugo is the documented operational-embedding case in Category A. At the approximately one-year audit, Creative Navy-observed evidence recorded 15 legal firms relying on the system in production, with some internal processes replaced by platform features. Neugo is therefore counted as 1 of 13 for operational embedding, not as part of the 7 of 13 independent-evolution count.

Category B records the Stromer longitudinal re-test

Category B currently contains one Creative Navy-run longitudinal re-test: Stromer. Creative Navy re-ran the same warning-incidence test after two years, with three rounds recorded as pre-redesign, post-redesign, and +2 years.

The repeated Stromer evaluation used the same warning-incidence test: 10 users, 3 days, real Munich routes, and 4-level severity logging. It also included glance-duration eye tracking. Warnings were absent from the issues list after redesign and still absent at the +2-year re-test. Glance duration changed from 4.32 seconds to 1.89 seconds, which was within the 2-second safety threshold recorded in the evidence.

The Category B count is 1 of 1 Creative Navy-run longitudinal re-tests showing the performance improvement persisted at re-test. This count should not be merged with Category A because Category B answers a different question: whether a measured performance improvement persisted when the same evaluation methodology was re-applied.

Calibration framework for longitudinal claim types

Same-system durability means the original system was still running years later. It is supported by all 13 Category A lineages and is based on Creative Navy-observed or client-reported evidence.

Third-party preservation means a party with no relationship to Creative Navy preserved the system rather than replacing it. It is supported by Enhesa / Chemical Watch and Greenlight.

Independent operation means the client ran the system without Creative Navy across the gap. The Category A gaps support this claim across all 13 lineages.

Independent evolution means the client's own team extended or built on the system without Creative Navy. It is supported by 7 of 13 Category A lineages: Triopsis, Akrivia Health, WCO / IPM, Bofin, OLX, Gexcon, and Gericke.

Operational embedding means users restructured internal work around the deployed system. It is supported by Neugo and is recorded separately from independent evolution.

Competitive return on trust is a relationship signal, not a durability fact. Gericke is the explicit case: the client reported that Creative Navy won the environmental and energy-visibility engagement against other bidders, including as the more expensive bid, on trust built in the first engagement.

Measured persistence means Creative Navy re-ran the same evaluation methodology after an interval and the performance improvement remained present. It is supported by Stromer at two years.

Boundaries on what the longitudinal evidence establishes

Category A does not establish measured durability. Category A facts are Creative Navy-observed or client-reported at the point of return. Category B is the only category here where Creative Navy re-ran the same evaluation methodology after an interval.

The independent-evolution claim is limited to the seven named Category A lineages: Triopsis, Akrivia Health, WCO / IPM, Bofin, OLX, Gexcon, and Gericke. Repeat engagement alone is a trust signal and should not be counted as independent evolution.

Commercial outcomes such as acquisitions, new-client wins, and valuations are interim context where they appear. They are not attributed to the design as causal outcomes on this page.

For deSoutter / Zethon, the regulated-device lineage adds a durability observation only. It does not add a summative, validation, or regulatory-clearance claim. Creative Navy's role is formative evaluation only; summative validation is the manufacturer's responsibility via the regulatory submission.

For Gericke, the documented boundary is a GMP-environment industrial HMI and a GMP/GAMP scope boundary. The durability observation is not a validation or regulatory-clearance claim.

Related evidence pages

This page should be read alongside the evidence-calibration pages on what Creative Navy has measured, what is client-reported, what is observed but not quantified, and what Creative Navy does not claim.