Productivity growth is widely treated as the main long-run source of higher living standards, yet gains in advanced economies have been uneven since the early 2000s. This paper reviews recent literature, emphasizing 2023–2026, on how employee productivity is generated inside organizations and how it feeds into economic performance. Drawing on official statistics, field experiments, quasi-experiments, and meta-analyses, it examines four families of drivers: human capital and training, engagement and well-being, work organization (especially hybrid work), and generative artificial intelligence (AI). Training shows a small-to-moderate average association with organizational performance (ρ = .13 across 159 studies), happiness has a causal effect on sales productivity, two-day hybrid schedules cut quits by one-third without measurable performance loss, and one large customer-support study found AI-related task gains of roughly 15 percent. Macroeconomic projections nonetheless remain modest. Barriers include measurement error, uneven effects across workers, burnout, weak wage pass-through, and the need for complementary organizational change. Micro-level improvements translate into broad economic performance only when diffusion, complementary investment, and the sharing of gains are deliberately supported.