One must be part statistician, part economist to figure out the NFL's system for awarding compensatory picks.

Those are picks awarded to teams that lose players to free agency and bigger contracts.

The theory is teams can maintain something of a competitive balance by way of artificially created draft positions outside the top 32 picks in rounds 3-7. Letting players leave to sign bigger contracts elsewhere is a strategy many successful organizations seem to employ; Baltimore and Green Bay are two of the league's least likely to retain current free agents, and both have been largely successful over the last six years.

Over the Cap, the best cap and contracts site available, has an excellent breakdown of compensatory picks and the process here.

Based on Over the Cap's highly elaborate formula - which is self-admittedly not going to be 100 percent accurate due to the fact the NFL does not disclose the exact formula for its compensatory picks - the Steelers look to gain a sixth round pick in the 2015 NFL Draft for losing Ziggy Hood to the Jaguars. Hood signed a $4 million average per year (APY) contract in Jacksonville, and after a process of elimination, Over the Cap came up with this:

After having reverse-engineered a formula through the assignment of benchmark levels based on APY (the key factor behind compensatory picks), the signings of certain players combined with the departure of others reduces itself to obtaining a sixth round pick.

Certain positions and dollar amounts qualify for certain levels of picks, so Over the Cap threw out this list of players as reasons why the Steelers may get an additional 1-3 picks, all in the seventh round.

There are four qualification changes to watch for:

LeGarrette Blount does not qualify

Darrius Heyward-Bey does not qualify

Arthur Moats does not qualify

Jonathan Dwyer does qualify

Such changes would result in the following:

If any one of the above happens, Pittsburgh will get a 7th for Jerricho Cotchery.

If any two of the above happens, Pittsburgh will get two 7ths for Jerricho Cotchery and Ryan Clark.

If any three or all four happen, Pittsburgh could possibly get a third 7th for David Johnson provided that he makes it past the 32-pick limit.

To simplify it, the Steelers look to gain at least one pick, and possibly as many as four picks, none of them coming before the sixth round.

If the Steelers have drafted any round well recently, it's been the sixth. With the obvious value of Antonio Brown, the Steelers already got a good return on Vince Williams, and look to duplicate that with an expected increase in playing time for Dan McCullers next year. The more picks, the better.

In case you were wondering, OTC projects a fourth round comp pick in 2016 should the Steelers let Jason Worilds walk in free agency this year.