# Aggregating rates of events in a population

For every 100,000 people, 4 people succumb to event $X$, a different 10 to $Y$, and 2 others to $Z$. I would like to know the number of people that succumb to any of $X$, $Y$ or $Z$ per 100,000. Is it as simple as $X$ + $Y$ + $Z$?

• If X can lead to Y and then the person dies, it may be difficult to classify if the person succumbed to X or Y. Otherwise it should be simple addition. – rnso Mar 24 '15 at 16:37
• Yes but the data I have is such that $X$, $Y$ and $Z$ are mutually exclusive – Brad Mar 24 '15 at 16:38
• It is common in medical articles where the causes of deaths are mentioned. And simple addition is expected to work there, unless X can lead to Y or Y to Z etc. If X, Y and Z are mutually exclusive, it should be simple addition. – rnso Mar 24 '15 at 16:40