Are there studies showing timer effectiveness?

As an e-commerce marketer, I'm constantly seeking data-driven evidence about conversion optimization tactics. I want to understand if countdown timers genuinely influence customer behavior or if they're just another trendy gimmick. Are there academic or industry studies that quantitatively prove the psychological impact of time-limited offers? I need concrete research that demonstrates how timers affect conversion rates, average order value, and customer decision-making processes across different industries and sales contexts.