I have become particular about “can” and “could” when asking for a favor or making a request to a customer for assistance while providing support. If you are looking for a positive reply, I suggest you do too. It is better to ask if someone “could” do something, versus asking them if they “can” do it. For some people, this may be obvious, for others it is not.
Forget about the fact that it is the “proper” word to use. Even remove the fact that it is the word with the most appropriate meaning for the situation (of course someone “can” respond to your survey – the question is will they).
As I’ve thought about why I think strongly enough to want to give advice to others to use “could”, I realize it comes down to this: “could” is less challenging than “can”. And when you are asking someone for a favor or assistance, you don’t want to challenge, you want to invite.
Think about getting an email that ends with either of these two sentences:
- Can you find 30 minutes out of your busy schedule so I can try to sell you something?
- Could you find 30 minutes out of your busy schedule so I can try to sell you something?
It is subtle yes – and important. There is a questioning tone of the person’s capability with “can”. Think of “can you or can’t you?” With “could” you are inferring they are capable, and are simply inquiring if they are willing.
I think you could also use “would”, and it is very close to “could”. In fact looking them both up in the dictionary on my Mac, I see that:
- For “could” the second definition is “used in making polite requests”
- For “would” the fourth definition is “expressing a polite request”
- For “can”, the word “polite” is nowhere in the definition
I have no question as to whether or not you can use “could”, and I suggest that you do when you don’t have a question of your recipient’s capability.