If you assigned your keywords to the appropriate position bid strategy in DoubleClick Search, be sure to verify the following:
Are you comparing equal time periods before and after the strategy was implemented?
Have you added any keywords to this bid strategy since it's been implemented? Make sure you're comparing like time periods and the same ad groups when analyzing bid strategy performance.
Is your target position attainable with the min/max strat bid range you have designated? If your Max CPC bid is equal, or close to, the designated max strat bid, and you’re not hitting your target average position, you'll need to raise the max strat bid to reach your goal. Similarly, if your Max CPC bid is at the min strat bid and the target position can't be reached, please lower the min strat bid.
If you have confirmed all of the above and you still have questions on whether your position bid strategy is working properly, contact your Technical Account Manager or DoubleClick Search support at ds-support@google.com for further assistance.