In the organisation I’ve been studying I’ve previously described that Instant Messaging (IM) makes a small contribution to the overall understanding of the organisational/social network but this did not tell us if there was anything to learn about when people communicate. To examine this I’ve summarised IMs and emails sent by day, day of week and hour:

The following chart shows daily activity over a two month period. Note that the dip in emails around 20/07/2013 is due to a number of missing Exchange Server log files.

It can be observed that email is more popular and that the pattern of email and IMs is fairly regular when viewed at this scale. The only slightly unexpected observation is that IMs are more popular mid-week whereas email is more mixed.

The next question is does time-of-day make a difference?

You can see some interesting differences emerging, but to make in clearer I have produced a chart showing the percentages of each communication mechanism:

Here you can see some clear trends: IMs are more likely to be made when people are first starting work (in the morning 07:00-09:00 and after lunch 13:00-14:00) whereas email dominates the end of the working day (16:00 onwards). Without further study it can only be speculation as to why this is but my theory is that IMs are used more informally and people who are socially close are exchanging greetings whereas Email is more formal and is used to evidence a day’s work complete.

And what about Wednesdays how does that look when we turn the actual numbers into percentages?

Well, yes, definitely Wednesday is the most popular day for IMs. I can offer absolutely no theory as-to why this is and I’d welcome any suggestions.

Follow