There is a proven relationship between contacts made and sales made. Which is why sales managers constantly push sales staff to be making calls. Sales has been around for way longer than development, the underlying theory for sales is well known. Just like the underlying theory for manufacturing is well known.
No there isn’t. There’s sometimes a correlation, but only people without knowledge of sales think that’s causal. If you want meaningful sales you have to approach it fundamentally differently than you seem to think. Your universal law of sales only applies to commoditized products, and if you’re selling those you’ve already lost.
