Thanks for your comments. First, our clients that use Send Time Optimization see a wide range of results. For some the lift in various metrics is very significant, some get a small lift – but still an increase – and some have seen no lift.

While we have yet to see a pattern of what verticals or message types that STO works best for, it clearly works really well for some companies and less so for others. There are also obviously numerous variables that might go into this – from demographics, to message cadence, content, brand recognition, offers, etc.

As for hypothesis – it is really quite simple. If you can increase the chance of having your message be near the top of someone’s inbox when they are more likely to be interacting with their emails, you may increase their likelihood to engage.