The CRA released a report looking at their average processing time for SR&ED claims that were submitted between April 1, 2010 and December 31, 2010. The results are:

Type of Claim Average Days within CRA’s control Average Days outside CRA’s control Total Average Time (days)*
Refundable claims
(submitted within 120 days)
39 29 68
Refundable claimant-adjusted claims
(submitted within 240 days)
100 43 143
Non-Refundable claims
(submitted within 365 days)
96 91 187
Non-Refundable claimant-adjusted claims
(submitted within 365 days)
145 126 271
All claims 69 48 118
* The average days within CRA’s control and the average days outside CRA’s control may not add up to the Total Average time due to rounding.

The processing time is the number of days that the CRA takes to process your claim from the moment your completed claim is filed to the time the review has been completed.

The column in the table that talks about delays outside of the CRA’s control includes time spent due to an incomplete claim being filed, an income tax return not being filed, the claimant taking a long amount of time to respond to review requests, etc.

Source