In agile development the timescale is fixed. So one thing you can be absolutely sure about, is that it'll deliver on time!

The question in agile development is the other way up - how can I be sure enough features will be delivered to achieve the objectives and realise the benefits? And the truth is, that's still a really tough question.

Unfortunately, no methodology - agile or otherwise - can completely mitigate the risks of software development, because it's inherently a potent cocktail of unpredictability (people, software, estimates, change).

However agile development does provide clear, measurable, visible progress on a frequent basis, so it goes a long way in mitigating risks and identifying issues early, while there's still time to react.

See also: Time waits for no man!