LinkedIn's decision to limit and charge for personalized connection requests on its free plan is a strong market signal. It suggests their internal data shows these messages are highly effective for users, justifying their monetization and contradicting studies that favor no message.
Studies suggesting personalized LinkedIn invites are less effective may be flawed. The data likely includes many low-quality, templated messages that are personalized "at scale" or contain an immediate sales pitch, which naturally perform worse than a neutral, note-free request.
Instead of sending a cold connection request, first find a prospect's recent post and leave a thoughtful comment. This "pre-engagement" warms up the interaction, making your subsequent personalized connection request far more likely to be accepted because you are no longer a stranger.
Prospects often accept note-free connection requests because it requires less mental effort. There is no potential sales pitch to analyze, allowing them to make a quick decision based on the profile alone. This bypasses the innate fear of a "bait and switch" that personalized messages can trigger.