JMIR Publications

ABSTRACT

Background:

Digital and knowledge work now concentrates much of the global workforce in front of screens for most of the working day, an exposure associated with visual strain, musculoskeletal and postural load, adverse environmental conditions, and psychological strain. These burdens can erode the capacity to sustain productive work, yet they are typically captured only intermittently and through self-report. Digital phenotyping — the in-situ quantification of individual-level human phenotypes from personal digital devices — offers a route to continuous, in-context measurement, but has so far been developed almost entirely for smartphone-based behavioral and mental-health monitoring.

Objective:

We propose the Digital Work Capacity Index (DWCI), a framework that extends digital phenotyping to the physical, cognitive, and environmental demands of desk-based work. The framework is intended to serve two aligned aims: helping individual workers protect long-term health while sustaining the focus their work requires, and giving organizations a measurable path to reducing health-related productivity loss.

Methods:

We synthesize evidence across occupational health, environmental science, and affective computing to identify the signals that reflect health- and focus-related strain during desk work. From this basis we define the framework's two composite axes — a Health Score and a Focus Score — together with their constituent signals and each signal's reference ranges and sources, prioritizing explainability over black-box prediction.

Results:

The framework organizes desk-work strain into two transparent composites. The Health Score integrates signals of visual, postural, environmental, and affective load; the Focus Score integrates behavioral signals of engagement and attentional continuity. Because each composite is built from measures with defined reference ranges, the resulting scores can be traced back to their contributing signals rather than to an opaque model.

Conclusions:

By treating productivity as a function constrained by health, the DWCI provides a workplace-specific, explainable measurement layer for continuously estimating functional work capacity. We specify a within-person validation study through which the framework's components and composite scores can be empirically tested. This is a conceptual framework; empirical validation is future work, and no primary data are reported here.