It's a long time since I've done stats as well, but I think you're thinking about this the wrong way. If you'd said at the start of the shift "ooh, I wonder what the odds of me going to grey close 3 times today are", you'd be closer to the mark. But you weren't - the first visit is nothing unusual, it's the repeats that are the coincidence. Say the first job was at Grey close. I think the odds of 2 repeat visits to a given street is something like: ( (housesInNewham / housesInGreyClose) ^ 2 ) / (jobsInDay - 1) Which is about 1 in 738,000. Still a big number, but a bit more believable. Also see the law of large numbers. "The law of truly large numbers says that with a large enough sample many odd coincidences are likely to happen." therefromhere.