Concatenated messages can only fit 153 characters instead of 160. For example, a 177 character message is sent as 2 messages. The first is sent with 153 characters and the second with 24 characters. The process of SMS concatenation can happen up to 4 times for most bulk SMS providers, which allows senders a maximum 612 character message per campaign.
Sample size indicates the size of the group of people who are going to receive your message. The size of this group and the amount of conversions you’re getting determines the significance of your test. Significance refers to whether we can rely on the made changes to have generated these results, or whether we can’t rely on the changes, but see that the results were simply due to chance. What this really means is that we want to be able to say: we can be 95% sure that the changes we made will improve our conversion rate.
To learn how your message can be improved, it’s important to analyse the results. Which parts of your message are not performing as well as expected? Is the open rate lower than expected? Or are people opening your message, but not taking any further action based on the contents of the message? Your analysis will tell you which parts of your message can do better and will help you to formulate your goal.