If there is a corelation, (and I havn't heard that there is, but if there is) it just means that people who tend to do good on standardized test A, tend to good on standardized test B. That's all.
People with a 4.0 GPA probably have a correlation to a higher LSAT score too, but if you have a 2.1 GPA and somehow pull a 177 LSAT, no need to explain, just thank God and be happy about it.