As you know, when you are working with agile methods, mainly with the Scrum, you need to assign two important metrics on sprint planning. The time estimates and the story points, and both are used to size the software project. Both are separate metrics, a user story with a large size can take less time than lightweight stories. Probably the fault on story points is the fact that they are arbitrary, so I have created a simple spreadsheet to help me on estimates and story-point metrics.
It’s usage is very simple. You fill the regular time for PERT estimates, calculated with the classic PERT formula for task estimates. For story-point calculations, assign levels to well known variables while you are working on software projects: knowledge (know-how) level, required research level, percentage of developers that will work on a task and the level of dedication that will take the task.
If you follow this Blog, you will find that this spreadsheet is based on later posts, so you can read back the both entries related to this spreadsheet:
The usage of the spreadsheet template is easy. You fill the regular time estimate or 
The spreadsheet itself, is customizable. The Fibonacci series is placed on the Confidence & Scale sheet, so many parameters are placed there. You can replace the Fibonacci scale by the 
The confidence level for PERT placed on the second sheet, is the official PERT formula confidence level, so try to don’t modify that scale. Currently the spreadsheet has 
You can download the spreadsheet template here, it is released under Creative Commons license, so you can modify as you want :)
Entries 
Daniel, con respecto a la plantilla, ¿Que tan precisa puede ser en los tiempos estimados?. Es decir, ¿La haz utilizado en proyectos de gran tamaño y con buenos resultados según los estimados?
Saludos.
El método PERT no lo invente yo, es bien conocido. Por otra parte, el ideal es usar el método PERT (para las estimaciones), con un equipo que realice Scrum Poker y se coloquen los tiempos obtenidos en el Scrum Poker para las tareas en la plantilla, como lo indican los posts anteriores, si a eso le sumas el método PERT para realizar la estimación, deberías obtener tiempos de desarrollo mas precisos.
Por otra parte, llevo usando la misma plantilla desde hace por lo menos 1 año con muy buenos resultados. La gracia de usar Scrum Poker y PERT es que se absorbe el tiempo que redunda en tareas de investigación que requieren problemas poco comunes, entre otros. Y claro, funciona siempre que contemples todas las actividades que se realizaran en el desarrollo.
[...] user story, you can find the spreadsheet on my article Scrum.org. 2009. Retrieved 2010-04-03.“A Tool for Sprint Planning”. Sprint Planning [...]
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