This calculator helps you decide what sample size is big enough.

If you've got two ads that have different click-through rates right now, how sure can you be that those ads will perform differently in the long run? Enter your clicks and CTR's for each ad in this form, and SplitTester will tell how how likely they are to have different long-term results.

Before deciding on a course of action, marketers need to find out why subscribers are no longer responsive.

Sometimes its the simple things well executed that bring the best results. This is certainly true in email marketing where a strong proposition clearly communicated will bring rewards.