When is the ideal time to hold a chat room event to accommodate the most users, in particular users with close vote privileges?

Question

I wanted to run a weekly, 1-hour event, and initially set the time, somewhat haphazardly, to my lunch hour, 9:00pm UTC (as I expected to be alone in participation at first anyway).

However, several users indicated interest, and one user expressed not being able to participate because 9:00pm UTC meant 2:30am IST (India Standard Time; and I imagine we have a lot of SO users there).

When is the ideal time to hold a 1-hour chat room event, to accommodate the most SO users?

Of course, this depends on the type(s) of users one wishes to attract. For example, for my event, I'd be ecstatic to learn

• which hour on a typical weekday has the most activity from users with >3k rep, or
• which hour on a typical weekday has the most moderation activity,

as these would correlate best to the type(s) of users I wish to attract.

^{* However one defines "activity"—whether "votes cast per hour" or "pages visited per hour," I have a feeling the results of most definitions would correlate well enough to determine an hour that's most likely to work well.}

I might attempt to write some Stack Exchange Data Explorer queries, but besides that my T-SQL isn't too great, I'm under the impression that these kinds of entire-site-wide/entire-user-wide queries are likely to time out. Perhaps though there'll be ways to restrict the queries enough to produce meaningful results.

Answer 1

Here's a query that counts the number of 3k+ users active on any given hour (ignoring the day) since '2013-10-01'.

Here's the same query, but distinguishing activity based on the day.

These queries are largely unoptimized - they're just the first way of doing it that came to mind. There could be plenty of ways of getting more in-depth results - feel free to extend it appropriately, I just provided the basic query.

The results show that the ideal time is largely focussed around 15:00 - 16:00 (UTC apparently), but the deviation in the intervals around that interval is not too great.

By just changing the ORDER BY, I get a nice little graph:

(x-axis is hour, y-axis is number of users)

Answer 2

tl;dr

1:30pm UTC to 2:30pm UTC might be the ideal time to hold a chat room event centered around moderation activity. (See the conclusion for a more qualified answer.)

---

Background

To make the event widely to users who review the close votes queue, an ideal solution might have come from being able to query for data on close vote reviews. However, that data isn't yet available, though possibly underway (see @Emracool's request and @Shog9's proposal). Data on close and reopen votes seemed a promising proxy, but I found not only that full timestamps weren't available on the Votes table, but also that this data stopped being available after June 25th, 2013 (due to internal refactoring).

So, what to use as a metric on activity?

@juergend, @rene, and @Dukeling all proposed some nice answers—measuring activity based on posts. @Dukeling also grouped his results by distinct users, which I thought was an insightful addition, since I'm looking to maximize exposure to active users, not just the busiest active users. I wasn't convinced though, about basing the metric on posts. Like @Dukeling commented himself, for example, higher rep users probably don't ask as many questions; and personally, while I agreed that answers and comments were good indicators of activity, I wasn't sure they'd correlate as well to moderation activity.

Suggested Edits

What about suggested edits (approvals and rejections)? After all, the suggested edits queue is the most popular of the queues (next to the close votes one), and it's strictly a moderation activity. Here's a plot of suggested edits approvals and rejections in 10-minute buckets:

SELECT
  Time,
  COUNT(*) Activity
FROM
(
  SELECT
    UserId,
    DATEADD(mi, DATEPART(hh, v.CreationDate)*60
      + DATEPART(mi, v.CreationDate)/30*30, 0) AS Time
  FROM SuggestedEditVotes v
  INNER JOIN Users ON Users.Id = v.UserId
  WHERE Users.Reputation >= 3000
) X
GROUP BY Time
ORDER BY Time

Suggested edits: approvals and rejections by >3k rep users per 30-minute window:

Interesting! Using suggested edits activity as a proxy for moderation activity, it appears the busiest window of time for moderation is between approximately 9:00am UTC and 2:00pm UTC!

At least two further adjustments can be made.

First, while doing some related research, I noticed a pattern: not only are there distinct slumps in moderation activity over the weekends, but hour-by-hour shapes on the weekend look different, too:

SELECT TOP 30
  CAST(CreationDate AS DATE) AS Date,
  MAX(Count(*)) OVER(PARTITION BY CAST(CreationDate AS DATE)) as Activity
FROM SuggestedEditVotes
GROUP BY CAST(CreationDate AS DATE)
ORDER BY Date DESC

Suggested edits: approvals and rejections per day:

Code omitted due to length. See query here.

Suggested edits: approvals and rejections by >3k rep users per 30-minute window:

So, first, let's filter out the weekend data, since I only plan to run my event on weekdays:

Suggested edits: approvals and rejections by >3k rep users per 30-minute window (weekdays):

Second, as @Dukeling first demonstrated, let's count distinct users, rather than distinct actions:

Distinct >3k rep users approving and rejecting suggested edits per 30-minute window (weekdays):

The queries are available here and here, respectively.

Conclusion

Analyzing only weekdays and the actions of users with >3k rep, it appears that

• 11:30 UTC to 12:30 UTC sees the greatest number of suggested edits approvals/rejections.
• 13:30 UTC to 14:30 UTC sees the greatest number of users approving/rejecting suggested edits.

Using suggested edits approvals and rejections as a proxy for moderation activity, these times seem ideal for holding a chat room event centered around moderation activity.

Answer 3

Based on this query only looking at new questions

select top 1 * 
from 
(
select datename(dw,creationdate) as dayofweek
, datepART(hh,creationdate) as hour
, count(*) as numofposts
from posts
where id > 15000000 -- limit due to timeouts
and posttypeid = 1 -- only questions
-- and creationdate > '2013-10-01' -- last month rougly
group by   datename(dw, creationdate)
, datepart(hh, creationdate)
) as t
order by 3 desc

the outcome is: 'Thursday' from 15:00 to 15:59 (I assume that is GMT/UTC...)