Second Answer
You are South (3rd seat, favorable). Partner showed a balanced hand with 12-14 HCP.
How likely is it, that you can make game in spades? Here is a guideline that we have found to be reliable: if you can construct perfect minimums for partner, that make game highly likely, then you have enough to invite game. We looked at very good 12 HCP hands for partner, but we weren’t able to construct any that would make four spades highly likely. Here is another method: your Losing Trick Count is eight, so partner would need to cover five losers to make game in spades. A useful guideline is that a 15-17 one notrump often (but not always) will provide four Cover Cards, so it’s not at all likely that partner (12-14) will provide five Cover Cards. So this method also suggests not inviting game. Of course, in your dreams, partner might have this sort of hand:
Partner Dream Hand 1: K102 AQ92 32 A1092
Your Hand: QJ953 J107 A6 QJ7
… on which you’re fairly likely to take ten tricks in spades. But partner is quite unlikely to hold such a hand. Summing up, it’s not at all likely that you could make game in spades.
How likely is it, that partner can make game in notrump?