Dollar cost averaging doesn't have a better expected value than lump sum investing, but it should have a lower variance, no?
Also, there's dollar cost averaging like "I have a lump sum now, but I will invest it slowly over the next 2 years" and there is dollar cost averaging like "I will invest money as it comes in slowly over the next 2 years instead of saving it up and investing it as a lump sum then". The former is the technical definition, but the latter is what most people mean when they use the term informally...
Also, there's dollar cost averaging like "I have a lump sum now, but I will invest it slowly over the next 2 years" and there is dollar cost averaging like "I will invest money as it comes in slowly over the next 2 years instead of saving it up and investing it as a lump sum then". The former is the technical definition, but the latter is what most people mean when they use the term informally...