It seems AtCoder is going to implement a new system where you choose if your participation in a contest is rated or unrated before you get to see the problems. Here are the full details from the site:
We developed a new system where one can choose Rated or Unrated participation in contests. We will introduce this system from ABC230 on 3rd Dec.
When registering for a rated contest, you can decide whether you want to be Rated or Unrated in advance. You can choose an option before the contest starts or in the first five minutes of the contest. If you choose Rated, your rating will be updated whether or not you open problems or make submissions.
In a rated contest, you can open problems only after you choose Rated or Unrated participation. If you don't choose an option and five minutes have passed after the contest starts, you are considered Unrated. Also, if your rating doesn't fall within the rated range of the contest, you are automatically regarded as Unrated.
We recommend you choose an option in the following way:
Rated: We encourage you to choose this option in general. Even if it's the first time you take part in a contest, we recommend this.
Unrated: If you don't expect your typical performance for some reason but still want to see the problems and solve them, use this option.
Before a contest starts, you can switch Rated/Unrated by first canceling your registration and then registering for the contest again. Note that, after the contest starts, you can't cancel your registration even if it's the first five minutes of the contest, and thus you cannot change the option.
I remember a few blogs being posted a while back, proposing a rule similar to this one to be implemented — I can't find any of them now though. I think the main reason this rule was implemented was so that people who planned on joining, but decided not to due to fear of a negative delta, will be included in rating calculation (please correct me here if I am wrong). There were multiple possible effects discussed, such as
People may miss the contest due to reasons beyond their control, giving them a huge loss of rating. I think this is addressed by the five minute grace period rule — people who may expect some problems in their current situation may choose to hold off on registration, and decide within the first five minutes of the contest if they are able to compete. This is enough time to accommodate people slightly late, who will not get a significant disadvantage by the loss of time had they joined the contest under "normal" rules.
People who make alt accounts can look at the problems beforehand using one account, and solve using another one. I don't think this will affect the standings much, as I feel five minutes is not enough to make a significant difference.
The number of people joining the contest will decrease. I feel like this will happen, due to possible confusion over the new system, and because of the way AtCoder calculates penalties based on the final submission instead of across all submissions, though I'm not too sure.
I'm really interested as to how this will go, and what effects the new change will have on the number of people joining, or how someone's average performance will change (or not change).
What are people's thoughts on this? Should Codeforces implement a similar rule to this also?
Before this change, one can register in an AtCoder contest and look at all the problems and decide not to submit if they think the outcome is not favorable. There is no penalty. I think this change announced today can fix the above.
They'll just create an alt account for this. There is no solution to malicious practices.
Actually new system is the solution, because earlier you were able to decide if you will participate during whole contest time and now you have only 5 minutes to make a decision no matter if you use alt account or not.
I'm a strong supporter of this change on several levels:
1: Previously, the AtCoder scoring system incentivized waiting to submit until after solving enough problems to be confident that you have enough points to increase your rating. This is bad for multiple reasons. First, subjectively, I think it makes for a less fun competition: problem difficulty information is less readily available because the scoreboard does not reflect the number of competitors who have solved each problem, making the contest strategy less interesting, and the scoreboard feels less dynamic when competitors tend to submit problems in one large batch rather than intermittently submitting problems throughout the contest. Second, I think that the resulting rating mechanism is a less reliable indicator of skill because it largely reflects best-case performance, rather than average-case performance, and because it provides a significant advantage to those who compete more frequently (because those individuals will experience more extreme positive outlier contests that will vastly improve their rating, while they do not have to submit during extreme negative outlier contests).
2: By allowing competitors to participate in contests without risking their rating, the new format removes one of the primary incentives to use alts. Now, competitors who don't want to risk their rating can still compete and can still appear in the standings, which means they're less likely to create alts in order to compete without losing rating.
3: The new unrated option is convenient for those who want to participate in a contest but know they won't be able to compete at peak level (due to e.g. being tired/sick, having to leave midway through the contest, etc). This is preferable to the existing system on e.g. Codeforces, where those not competing officially can read the problems but have no way of submitting code.
4: For competitors who don't want to risk their rating, I think unrated competition is a more fun alternative to virtual participation. There are a number of reasons that unrated participation that coincides with the official contest is different from participating virtually after the fact (for example, unrated participants can join the discussion occurring immediately after the contest, can watch the scoreboard as it unfolds, and are at no risk of being spoiled on the problems). It's hard to figure out why, but I don't find virtual participation in contests as fun as competing officially in a contest, while I do think I'd find unrated participation more exciting.
That said, I'm not sure the AtCoder system completely removes the incentives to use alts. Under the new AtCoder system, it would be possible to register on an alt and read the problems before deciding whether to choose rated or unrated participation on your main account. Instead, I would suggest either (a) allowing competitors to read problems before choosing between the rated and unrated options (but still requiring them to choose within the first five minutes) or (b) requiring competitors to choose rated or unrated participation before the start of the contest. Which of these options is preferable largely depends on what sort of rating system AtCoder wants to create. For example, on Codeforces, the fact that I can read the problems before deciding whether to compete officially allows me to avoid rated contests that include geometry problems, since geometry is my weakest area. I think there's a reasonable argument that Codeforces shouldn't allow me to choose contests that way and should force me to try a difficult geometry problem every now and again in order to keep my rating.
Overall, though, I think this update is a step in the right direction, and I would like to see it implemented on Codeforces. If an unrated option is added to Codeforces, though, it would be best to prioritize rated users' submissions above unrated users in the judging queue in order to minimize the risk that a contest must be unrated because rated users' submissions are processed too slowly.
Thanks to the AtCoder admins for the update! I'm very impressed with all of the work AtCoder has done to improve their platform's user experience, and I appreciate the careful thought their admins have put into these changes.
Noobs are worried about the rating while gods solve problems.
Wow now most of them will be participating so more competitiveness Yay....
I have a doubt. Like, I registered for a contest and forgot to select any of the rated/unrated options, so by default will I be a rated or an unrated participant?
No, you register by choosing one option.
But my name shows up in the standings table without even choosing one option.
The first contest under this new rules and options will be tomorrow, so any standings table your are today in is independent of it. Also, the standings table may include all participant, rated or unrated, depending on the options you choose to display the table.
Just give it a try, register for tomorrows abc. You can unregister immediatly if you wish.