.

Esta expresión es de uso más frecuente y, a la vez, una traducción menos "literal" de "metrics".
En estricto rigor, en inglés "metric" hace referencia al uso del sistema métrico (metros, cm, etc.) y no a la acción de medir propiamente tal.

Oxford Dictionary:
metric = adjective, relating to or using the metric system
Cambridge Dictionary:
metric = using or relating to a system of measurement that uses metres, centimetres, litres etc.

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Note added at 2 hrs (2009-09-29 02:34:18 GMT)
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Clarification:
The use of "métrica" in Spanish is wrong in this context. In Spanish, "métrica" means (according to the RAE):
A. (noun) Arte que trata de la medida o estructura de los versos, de sus clases y de las distintas combinaciones que con ellos pueden formarse.
B.
1. adj. Perteneciente o relativo al metro (‖ unidad de longitud). Sistema métrico.
2. adj. Perteneciente o relativo al metro (‖ medida del verso).

The same can be said of the English term "metrics". The only accepted meaning in all English dictionaries is:
"A part of prosody that deals with metrical structure."
or
"The use or study of metrical structures in verse; prosody."
or
"The science or art of writing in meter."
etc.

In short, in this case both "métrica" and "metrics" are examples of poor language usage. From the context provided, it is obvious that "métrica" (though wrongly used) refers to the act of measuring or assessing performance objectives. So why not use a straightforward term like "measure" or measurement" when this is what is actually meant?
Simply google "quantitative measure(ment) of performance" and "quantitative metrics of performance", and you will see that the former is a lot more frequent.