How much does the context add to this posture score?

Enter a REBA score for the posture, then the four conditions the published ECERI model amplifies it by: working height, surface condition, slope, and distance to an unprotected edge. The result is the same REBA score with its surroundings put back, on REBA's own five categories, so a task can be read with and without its context.

Start from an archetype iThe five archetypes from the paper, with their anchor values. Roofing: 8 m, challenging surface, 30 degrees, 1.0 m from the edge. Structural steel: 25 m, fair surface, 5 degrees, 1.5 m. Facade scaffold: 12 m, challenging, level, 0.8 m. Aerial lift: 15 m, optimal, level, 0.5 m. Ground level: nothing amplifying. An archetype fills the four conditions only. The REBA score stays yours.

REBA score for the posture iThe Rapid Entire Body Assessment score from the REBA worksheet or a validated app, before any context. Score the most frequent posture (held for 30 percent of the cycle or more) or the most extreme posture held for 10 percent or more; for static work, score the sustained posture. The categories are REBA's own: 1 negligible, 2 to 3 low, 4 to 7 medium, 8 to 10 high, 11 and above very high.7 · Medium Working height iVertical distance from the standing surface to the nearest stable ground or reference plane, taken at the foot position on a slope and at the midpoint of the work zone for a mobile task. Enter the real height even when fall arrest is worn: the cautious movement and the reduced reach that height brings do not go away with a harness. OSHA requires fall protection from 1.8 m (6 ft). Above about 15 m the height term is close to its ceiling.10 m

Surface condition i0 Optimal: dry, clean and uniform (dry plywood, steel grating). 1 Fair: minor debris or moisture (sawdust, dew, dust). 2 Challenging: uneven, oily or wet (wet metal, ice patches, gravel, oil). 3 Hazardous: slippery, loose or irregular (continuous ice, thick oil, gaps over 25 mm, unconsolidated material). When unsure, pick the higher rating.

Slope of the working surface iDegrees from horizontal along the direction of work or travel (ridge to eave on a roof); for cross-slope exposure use the steeper angle. A digital inclinometer, a phone clinometer, or the BIM geometry gives it. Roof pitch converts as the arctangent of rise over run: 4:12 is about 18 degrees, 6:12 about 27, 8:12 about 34. OSHA treats a roof at 4:12 or less as low slope.15°

Nearest edge iA compliant guardrail (top rail at 42 inches, 200 lb capacity, mid-rail, toe board) makes an edge protected. The paper's field protocol counts distance to the nearest edge without one, so with a guarded edge the edge term is zero and the distance below is not used. A warning line or a personal fall arrest system does not make the edge protected for this input.

Distance to the unprotected edge iHorizontal distance from the foot position, or the planned position, to the nearest unprotected edge or opening, by tape, laser rangefinder, or site plan. Closer than 0.5 m is critical and the term rises steeply; beyond 3 m the term is zero. OSHA 1926.502 calls for guardrails, fall arrest, or warning lines near unprotected edges.1.5 m

Read the note

7.7 ECERI

Context-amplified risk

High

+10% amplification (ceiling 40%)

Medium to High REBA category to ECERI category

Height dominant amplifier

2.8 pts to the next category

ECERI across working height iThe score for this posture at every working height from grade to 30 m, with the surface, slope, and edge inputs held as entered. The dashed lines are the REBA score without context and the category boundaries. The height term is sublinear (exponent 0.8), so the curve rises fastest in the first few metres and flattens toward the ceiling.

ECERI at these inputsREBA alone and category boundaries

Where to act

Where the amplification comes from iEach bar is a term of the amplification, in points of the 40-point ceiling, against the most that term can add: 10 for height, 6.7 for surface, 10 for slope, 6.7 for edge, and 6.7 for the three interaction terms together (height with slope 3.3, height with surface 1.7, surface with edge 1.7).

Foundations

The formula, weights, exponents, and categories are taken from the published model without change:

ECERI: a context-aware extension of REBA for elevated construction ergonomic risk (Author's Research, Journal of Safety Research, 2026): the amplification model and its field measurement protocol
REBA, Hignett and McAtamney (2000): the baseline posture score and the five action categories this index preserves
OSHA 29 CFR 1926 Subpart M: fall protection from 1.8 m (1926.501), guardrail and warning line criteria (1926.502), and the low-slope roof definition (1926.500)
Revised NIOSH Lifting Equation, Waters and others (1994): the precedent for multipliers that scale a baseline load rather than add to it

Planning aid. ECERI amplifies a REBA score; it does not replace a REBA assessment by a trained assessor, the site fall-protection plan, or OSHA requirements. The category thresholds are REBA's, applied to the rounded score.