Than who? Mihawk? I highly doubt Shanks is weaker than Mihawk...he's weaker in swordsmanship. It's clear, and we have enough evidence that Oda intends for the WSS to stand for being the strongest at swordsmanship, and things like internal penetration, haki barriers and nukes give way for inferior swordsman to compete, it is clear Shanks will have the edge in overall haki mastery, specifically in CoC mastery over Mihawk. Looking at the difference in portrayal and treatment there is just no way Oda intends on Mihawk being Shank's clear superior. At best it's supposed to be ambiguous thanks to Mihawk's title, but Shanks is always pushing boundaries redefining power levels while Mihawk is hard to even pick out from Warlords most the time. MF was bad enough but the trend only continued post timeskip, where Mihawk has equal partnership with Crocodile, working under a clown, while Shanks is busy making an Admiral twerk and 0.5 shotting someone who put another Yonkou in the dirt. Oda has no intention of making Mihawk stronger than Shanks, none at all. In the battlefield of the strongest, Shanks had everyone holding their breaths and even Akainu sweating, meanwhile you could hardly tell the difference between Mihawk and Mingo in presence.
At best you can say they are in their own lanes stylistically, but calling Shanks inferior to Mihawk at this point just sounds like a bad joke honestly. Let's just say they are relative to each other and move on to save face for Oda.