¿Qué es una escala de estimación Agile?
Una escala de estimación es el conjunto compartido de etiquetas con el que un equipo compara elementos del backlog. Pueden ser números o categorías: son referencias relativas, no una tabla de conversión a horas. Scrum no prescribe Story Points, Planning Poker ni una escala concreta, por lo que cada equipo debe elegir y calibrar su enfoque.
Comparativa de escalas de estimación Agile
| Escala | Valores | Ideal para | Característica principal |
|---|---|---|---|
| Fibonacci | 0, 1, 2, 3, 5, 8, 13, 21 | Story-level estimation | Gaps grow with uncertainty |
| Modified Fibonacci | 0, 0.5, 1, 2, 3, 5, 8, 13, 20, 40, 100 | Mixed-size backlogs | Adds broad high-end buckets |
| T-Shirt Sizes | XS, S, M, L, XL, XXL | Early, coarse sizing | Fast categorical comparison |
| Powers of 2 | 1, 2, 4, 8, 16, 32, 64 | Teams wanting clear separation | Every step doubles |
| Linear 1–10 | 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 | New teams and simple workshops | Familiar but more granular |
Fibonacci
The familiar 0, 1, 2, 3, 5, 8, 13 and 21 deck gives small work fine distinctions and larger work wider gaps. Those gaps acknowledge that uncertainty usually grows with size. Treat 13 or 21 as a prompt to ask whether the item should be split, not as a promise of duration.
Modified Fibonacci
This deck adds 0.5 and replaces the distant high end with 20, 40 and 100. It is useful when a team sizes tiny changes and coarse initiatives in one workshop. A 40 or 100 should normally trigger decomposition before sprint planning.
T-Shirt Sizes
XS through XXL works well when speed matters more than arithmetic: roadmap shaping, discovery or an initial pass over epics. The values are ordered, so mode, distribution and spread are meaningful; a numeric average is not.
Powers of 2
A 1, 2, 4, 8, 16, 32 and 64 deck forces a clear choice: each card is twice its neighbour. It suits teams that prefer strong separation, although discussion can drift into whether work is literally twice as large.
Linear 1–10
A linear scale is easy to explain and can suit workshops where participants are new to relative estimation. Because adjacent choices are close, teams should avoid debating 6 versus 7 as if either were precise.
Fibonacci vs Modified Fibonacci
Both widen gaps as size grows. Standard Fibonacci is compact and encourages earlier splitting; Modified Fibonacci preserves very small and very large buckets for broader backlog work.
Fibonacci vs T-Shirt Sizes
Fibonacci supports numerical Story Points and velocity trends. T-Shirt Sizes are intentionally coarser and often faster. Teams can size epics with T-shirts, split them, then estimate resulting stories with Fibonacci.
Fibonacci vs Powers of 2
Both reduce false precision. Powers of 2 creates stronger separation, while Fibonacci offers more choices near the small end. Neither is inherently more accurate; consistency and reference items matter more.
¿Qué escala debería usar tu equipo?
Empieza con Fibonacci si quieres una opción conocida. Usa Fibonacci modificado si necesitas visualizar elementos muy grandes antes de dividirlos. Elige tallas de camiseta para trabajo rápido y aproximado de portfolio o discovery. Las potencias de 2 hacen inequívocas las diferencias de tamaño. La escala lineal 1–10 resulta intuitiva, pero sus valores adyacentes pueden crear falsa precisión. Mantén la escala el tiempo suficiente para crear historias de referencia estables.
Cómo usar estas escalas en PokerScrum
Elige el método antes de crear la sala. Todos los participantes reciben el mismo deck. Los votos permanecen ocultos hasta el reveal; después, compara las estimaciones más alta y más baja, aclara supuestos y vuelve a votar si aparece información nueva. Las cartas de interrogación y café siguen disponibles.
Crear una sala de Scrum Poker