I was invited at a conference to give a contributed talk. I was given 12 minutes to speak and 3 minutes for Q&A, but to keep my talk simple I didn't go in details (probably I spoke faster also). In all, I finished the talk in ~10 minutes. I know this somewhat disturbs the flow of the schedule, but it also gives more time for discussion.
What is the general impression in such cases? Is it bad to finish your talk early?
Getting the timing on a talk exactly right is difficult, and it’s much better to go short than long. So I wouldn’t worry about it. Similarly ending a 50 minute talk at 45 minutes is totally fine. Plus it gives people more time for questions.
Do not overthink about the past. What has been done, has been done. The only feeling about the general impression you gave is the feedback you got from questions from the audience, at the talk or from "chit-chat" you had after your talk. And we cannot judge them, because we were not there.
The outcome of a talk at a conference can be that you raised the interest of
There is no such a thing as a bad impression. Scientists and researchers are too busy and quite good at forgetting, being focused only on things relevant to their own research.
If you have the feeling you left a bad impression, because of no questions or very simple and courteous questions, let it go. You can be 100% sure that even if you presented deeply wrong results, a couple of weeks afterwards no one will remember about them. So the worst it may happen is that your talk went unnoticed.
Now, focus about what you learned, not about the impression of you from "the others".
You learned that you can give a talk without much details in 10 minutes.
Therefore, you know that next time you can go into details for at least 2 minutes. Or you can spare 2 minutes of simple things and of introduction and go into details for 4 minutes.
Most folks perform faster than they rehearsed, due to nervousness.Presenting is a performance.
Over time you'll learn how to allow for this, how to set time-check points in your presentation so you know if you're ahead or behind, and how to bring yourself down to a more relaxed speed.
Call it a learning experience and don't worry about it. It's happened to all of us. I once blasted through an overseas business presentation that I expected to take all day in the first hour; now that is embarrassing.
And remember: If you finish early, calling for questions from the audience will often consume as much time as you let it.
As there are very often speakers who take longer than they are supposed to (and thus either cause delays or take time away from questions), it is not very disturbing to have someone speak a bit shorter.
Also, if you managed to say everything you wanted to say in a slightly shorter amount of time, that is fine, as you did not fill your talk with unnecessary extra words.
It's hard to say without seeing the actual talk. In fact, the opposite could be more likely: presenters squeeze in too much and end up talking too fast, missing the main points, leaving no time for questions, or going over the time. So finishing a couple of minutes early could be quite refreshing.
If you'd like to improve for future talks, here's a checklist, which I used after hearing a professor snore during my statistics talk:
There are plenty of things you'll improve with each new conference. (That snoring disaster turned out quite valuable.) But there isn't any need to worry or strive for perfection.
A 10 min talk with 3 minutes of actual Q&A is no worse for the scheduling of the conference than a 12 min talk with 1 minute of actual Q&A. And a 10 min talk with 5 min of Q&A is better for scheduling than a 12 minute talk with 5 min of Q&A. -- So I wouldn't worry about schedule flow when you're asking about giving a shorter talk.
Going too long is an obvious problem -- if you're too long you short-change other parts of the schedule. Going too short isn't necessarily an issue. You either leave more time for Q&A, or you give people a slight bit more time to discuss things privately with their neighbors.
Instead, I'd worry about the content of your talk. There's a certain expectation of "substance" for a 12 min talk. Depending on your presentation style, you could hit that at 12 minutes, but you could certainly also be efficient and convey all that in 10 minutes. There are also people out there who could drone on for 20 minutes and still not reach that point. The issue with short talks isn't the time in and of itself, but rather that it's harder to put enough "substance" into the limited time period.
Note that "substance" here is effective substance. Rattling off a bunch of facts in rapid succession isn't effective substance, as no one listening can take it all in. You need to be able to communicate the substance, and that actually may involve presenting less, but slowing things down such that the audience can actually take it all in properly. But on the flip side, slower isn't always better. A concise delivery of points can be more effective than a detailed belaboring.
My recommendation would be to look at your presentation not from a time perspective, but from an effective communication perspective. Did you manage to cover enough "substance" in your talk for a 12+3 timeslot, or was it too thin? Was your delivery an effective communication of that substance, or did you hurry through it too fast/too ineffectively?
It's sometimes hard to gauge from the podium, but the attention of the audience is often a decent proxy. If you've covered the points you want to, and the audience is engaged throughout, then you've done well. If they've checked out at 7 min because they can't follow, that's bad. (If there was someone in the audience you trust for honest evaluation, I'd ask them for their opinion.) You can also sometimes get a sense of how the presentation went from the Q&A. If there's a bunch of basic questions you covered in the talk, then you may have gone too quickly and lost a bunch of people. If there's basic questions you didn't cover, you need to add detail. If there's a fair number of interested, advanced questions, you've probably done well. If there are close to no questions, then either you've bored everybody (so they no longer care), confused everybody to the point where they're afraid to ask questions, or did such a great job that you've addresses all the issues. (The last tends not to happen in practice.)
I know this somewhat disturbs the flow of the schedule, but it also gives more time for discussion.
None of these are serious issues. But I will claim that speaking fast is a problem, especially if you're also trying to "squeeze in" material. When you first hear about a subject you're unfamiliar with, some kind of novelty, the points and arguments require more time to sink in. Now, even 15 minutes is not enough, but try to artificially slow down your speech; and leave an informative slide (e.g. with a diagram or chart) up for longer than you need to describe what's on it. Take less short-cuts in your rhetoric and with your formal argumentation - even at the price of saying less things / going into less detail.
PS - I have this problem all the time, even after attending a bunch of conferences already. So, I might as well preach this to myself :-P
