How do you calculate my prior open rate and lift in my Smart Send Time results?
To calculate your prior open rate, Klaviyo looks at the hours during which you had been sending campaigns before using Smart Send Time. It then takes a weighted average of the open rates at those hours based on your exploratory data. Once we have the weighted average of open rates, we compare this with the open rate at your initial optimal time and calculate the lift. It’s not possible to take the simple average open rate across your campaigns because this would not handle subject line differences or outliers across your campaigns well. Instead, we use your exploratory data because these were the same campaigns going out across all hours.