No, this has nothing to do with the prevailing wage. You'll notice that each row indicates the "prevailing wage", as well as the wage that the company is actually asking to pay someone.

The prevailing wage is always way lower (and a joke, basically), satisfying their obligation to pay greater than or equal to, but that is not the interesting part of this data.

To be clear - this isn't a link to the LCA data (although each application includes it). This is actual individual salaries that were approved to a worker.

I'm not saying you should look at prevailing wage to see how much you should get paid. I'm saying that prevailing wage (listed on each application) is an indication of how much the employers' estimates of salaries for purposes of low-balling their foreign staff are out of touch with reality. I was too embarrassed to share my actual salary, which was higher than their 'prevailing' wage, but still pitifully small.

That is primarily because the prevailing wage is calculated by agencies like erieri and Cal EDD (in the case of California) surveys which are usually nine months to a year old. So ymmv. If the survey was taken during a boom year and is used in a bust year, the prevailing wages are usually higher than market. The reverse is also true. There is also a selection bias in the data as they only have data from organizations which are willing to share this. There is no mandated requirement for this.

Another thing to keep in mind is that (in theory) prevailing wage data reflects market wages (i.e. all types of engineers) not just those on a visa. Whether or not this is actually what happens is something I have not idea about.

So in theory the LCA data should be a good datum to start your salary negotiations on. However it should be tempered by current market conditions, location and most importantly your own position in the negotiations. Its always easier to negotiate from a position of strength. When you are looking to provide for your family, insurance, rent/mortgage etc and are unemployed, negotiating may or may not work depending on how desperate you are.