David Leonhardt tells us to listen to Michael Greenstone:
The red line is the usual picture of median earnings for full-time men. The problem with this line is that the percentage of men working over time has been declining over time. This attrition or dropping out of the labor force is not random, though, as the decline in full-time work it is disproportionately concentrated among low-skill men. This means that the red line is being propped up by the fact that it is increasingly comprised of higher skilled men.
One sensible correction for this is to calculate the median wage for all men (not just the full-time workers). This is the blue line in the below graph.
Why is this important? The full-time sample (red line) suggests that median wages have been stagnant since 1969.
I would raise the slope of the blue line back to zero: TV and video technologies are a lot better than they were in 1969. And there is the internet. But these improvements do not contribute very much to measured real earnings because we do not spend much money on them--even though we spend a huge amount of our recreational time on them.