DESI-18: Dyadic Emotional Safety and Inclusion Instrument — Development and Validation

The DESI-18 is a 16-item partner-rated psychometric instrument measuring dyadic belonging across four factors: Engagement (ENG), Responsiveness (RSP), Relational Attunement and Perceived Safety (RAP), and Warmth / We-ness Satisfied (WNS). It is grounded in Social Identity Theory (Tajfel & Turner, 1979; Stevenson & Bowe, 2022) and designed for use in single-session stranger-dyad contexts. The respondent reports on what their partner is offering, not on how they themselves feel — that partner-rated vantage is the design choice that distinguishes DESI-18 from existing belonging and closeness measures. Item structure: 16 scored items + 1 attention check + 1 global criterion (18 administered), which is where the "DESI-18" name comes from. Current version v6.1.2 (June 2026) — same architecture as v6.1.1, with the RAP factor renamed from Rapport to Relational Attunement and Perceived Safety to match the construct the items actually index. Development spans six generations (Gen 0–5, 2019–2026), from physiological observation through NSI behavioural coding to the current partner-rated self-report architecture. The instrument was developed by Vince J. de Blauwe (UEL / NTU) with NTU supervision by Prof. Clifford Stevenson (supervisor for the BUDDY trial and the DESI-18 exploration and validation) and UEL supervision by Dr Antonio Fidalgo (FRIEND feasibility study and the DESI-12 / DESI-14 lineage). This project contains five components: A — Instrument v6.1.2 (item bank, scoring syntax, administration guide, one-page quick-start). PUBLIC. B — Theory and PPI (construct validity argument, Stevenson SIT reframe, stakeholder consultation, PPI engagement log). PUBLIC from 15 July 2026. C — Validation Protocol (600-dyad multi-site Registered Report — six sites A–F, four confirmed: NTU, VIVES, Thomas More, U. Oregon; two slots held open for late-confirming partners; data collection from February 2027). PRIVATE until Stage 1 In-Principle Acceptance. D — Lineage Archive (Gen 0–5 development trail; documents prior to May 2026 appear under the name Vanhoutte — same researcher, name change formalised May 2026, ORCID 0009-0004-8975-6249 is the persistent identifier). PUBLIC — open audit trail. E — Publications (preprints, accepted manuscripts, conference outputs, applied derivatives). PUBLIC — populated as outputs land. Development paper: de Blauwe, V. J., Stevenson, C., & Fidalgo, A. (2026). Measuring felt safety where it can actually be seen. PsyArXiv. https://doi.org/10.31234/osf.io/65sdb DYAD programme placement: DESI-18 is the instrument anchor of the Y-pillar (Yoked Analysis), which it shares with LENS (osf.io/rm6wx). Umbrella programme: DYAD — Dyadic Inquiry, Analysis, and Design (osf.io/s8wf3). Related projects: FRIEND feasibility study (D-pillar) · osf.io/4c28b BUDDY trial programme (A-pillar) · osf.io/7nau9 LENS frameworks (Y-pillar sibling) · osf.io/rm6wx DYAD umbrella · osf.io/s8wf3 Maintainer: Vince J. de Blauwe · ORCID 0009-0004-8975-6249 Licence: CC BY 4.0 · Public release: 15 July 2026