Zia Mahmood says in his book Bridge, My Way that if your partner is an underbidder you shouldn't try and compensate for her by overbidding, and likewise if your partner tends to overbid you shouldn't compensate for that either. I think the idea is that although trying to account for your partner's bidding might get you a better result on the particular hand you do it on, they'll then keep on bidding that way. Instead, bid normally, and let them get to the wrong contract a few times then they'll correct their ways.
Anna is relatively timid, and I was guilty of trying to compensate for her in a hand last week. Even though I had opened 1NT so she knew our combined strength much better than me I still took matters into my own hands and doubled the final contract, when it should have been her. In a sense I was right to double, as it went two off, but next time I'll try and pass.
I opened the South hand with a maximum 1NT. Playing natural methods, West overcalled 2♣ and North made a weak take-out to 2♠. This was passed round to West who doubled for takeout. East was tempted by a Pass (2♠x probably goes one off, losing two Spades, two Hearts, a Diamond and a Club but might make if West is on lead a lot) but finally went for 3♦, which West recklessly converted to 3♦, hoping that it was her partner who held all of the outstanding points.
As it was, North had two vital high cards, which combined with the 1NT opening in South should have been enough for a double. Unless, of course, North believed that West had a long Club suit, and was hoping to make 3NT based on that. When it came round to me as South I knew that the Clubs weren't running so risked a double.
North lead the ♠T, covered in dummy. I presumed West had the singleton Ace and ducked, letting dummy's ♠Q hold the trick. Declarer took a successful Heart finesse then played on Diamonds, leading low from hand. North popped up with the ♦Q and lead a Spade to my ♠K, and I was then able to set up two Heart tricks for the defence, to go with one Spade (as North never got her ♠A), two Diamonds and the ♣K at the end. Six tricks for the defence meant 3NTx-2.
Declarer does better to play on Diamonds straightaway, and although short of dummy entries may just be able to stumble home with a Spade, two Hearts, three Diamonds and three Clubs. Without those Heart tricks it's not clear where the defence's tricks are coming from, and they could be limited to two Spades and two Diamonds.