Trying to compare the effectiveness of advertising between two different social platforms is pretty much like comparing apples to oranges, because every social network has its own advantages when it comes to marketing.
On top of the differences of the platforms themselves, effectiveness also entirely depends on several other factors:
Target audience: If you want to access a really broad audience and need a lot of options to get your message across, YouTube ads might be the better option. However, if your target audience is skewed younger (from 18 up to 35 years of age), TikTok is the way to go every single time.
Campaign objectives: TikTok is the perfect platform for any brand that’s looking to create brand or product awareness and/or recognition amongst younger audiences, and who want to see substantial engagement figures for their advertising campaign. YouTube is generally seen as an ad platform promoting click-throughs while TikTok is more passive and not as action-oriented.
Budget: The amount you’re happy to spend on your advertising is going to play a huge part in which platform you choose. YouTube’s CPM cost is lower than TikTok’s, but its average engagement rate is also substantially lower.
Product being advertised: If you’re advertising a particular product, what that is will determine the most appropriate social network that should be used. Fashion, beauty and fitness products, for example, work really well on TikTok.