The traffic split percentage in my test is set at 50%. Then why is variation attracting more traffic than Control.
VWO randomly splits your website traffic between control and variations. When visitors access a test page, VWO generates a random number for each visitor that determines which version to display for a visitor.
Because the traffic is divided randomly, the initial traffic split may not be exact 50/50 (variations / control may register unequal number of visitors). However, during the course of the campaign, VWO tries to bridge the gap and get the split percentage closer to 50/50.
Splitting traffic for split URL campaign
In split URL campaign, VWO automatically redirects your website visitors to the specified variation based on the split percentage you have set. However, in some cases (5-10%) the redirection fails due to some plugins installed by the visitors, or their browser settings. In such situations, you may notice that variations are receiving lesser traffic as compared to control.
How website traffic split affects your campaign results
In VWO, traffic split ratio has minimal statistical significance and does not affect your campaign reports. VWO calculates campaign results based on the conversion rates between variations (or control and variation), and not based on the number of visitors each variation receives. Be assured that your VWO test results are valid and reliable even with the minor differences in the traffic split ratio.