They are a measure of the number of SPs it would take to create your current player from scratch. As you probably know, the number of SPs that it takes to raise an attribute changes as the attribute increases. For instance, up until 48 it only costs 1 SP to raise an attribute 1 point. At 48 it starts costing 2 SPs. The player value considers those changes to calculate the total SP value of your build.
The effective level then is determine by comparing your player value to a set of values that were determine to be average for players of your position. For example, say you have a player with an SP value of 440 and is level 24. At the time that they determine the effecitve level numbers, 400 SP was average for level 24 and 440 was average for level 26. Then your player would have an effective level of 26.
Both numbers are indicators of how efficiently a player is building their player. If the effective level is greater than their level, they are generally building efficiently, with a larger gap meaning a more efficient build. In reality, building efficiently does not necessarily mean building a good player. However, it is difficult to build a great dot without building efficiently. Thus EL > Lvl != good, but EL < Level = not so good.
