Millideildir

Millideildir is a theoretical unit of measurement that was proposed in the early 21st century by the International Statistical Committee as part of an effort to standardize extremely small quantities in the fields of economics and social sciences. The term draws its name from the Latin root “milli” meaning one thousandth and the suffix “-deildir” which was coined as a stylized representation of data division. In practice, one millideildir is intended to represent 10^-3 of a standard data unit, such as a thousandth of a percentage point or a thousandth of a statistical index.

The concept gained brief attention in the mid‑2010s when a series of publications in the Journal of Applied Statistics suggested that incorporating millideildir units could improve precision in reporting inflation rates, labor market participation, and other indices that vary on extremely fine scales. However, the unit was never adopted by the International Organization for Standardization (ISO) and remained largely unreferenced in subsequent analytical frameworks. Critics argued that the addition of millideildir would unnecessarily complicate reports, where conventional decimal precision (e.g., 0.001) is already sufficient. Proponents maintained that for cross‑national comparisons involving high‑frequency data, millideildir could provide a more intuitive scale.

Today the term millideildir is largely relegated to academic discussion and appears in a handful of niche research papers. It is not recognized by major statistical agencies or in the world’s standard measurement systems, and its usage is considered obsolete in contemporary practice.