this is not mine! X post from another subreddit

The Massachusetts Supreme Judicial Court (SJC) studied gender bias, finding

In general, our evidence suggests that the courts hold higher standards for mothers than fathers in custody determinations.

Mark Rosenthal penned a favorite MRA criticism in a poor attempt to discredit the report. Some major flaws of his response:

(1) Rosenthal ignores the unanimous consensus of a huge body of research. With laser like focus, Rosenthal takes issue with only a single sentence from this single report, which claimed,

Refuting complaints that the bias in favor of mothers was pervasive, we found that fathers who actively seek custody obtain either primary or joint physical custody over 70% of the time.

Even if he managed to discredit this sentence, he's got a huge wall ahead (PDF):

gender bias studies commissioned by at least forty states, along with many local court districts, have unanimously confirmed the existence of pervasive bias against protective mothers vis-á-vis litigating fathers.

Rosenthal treats the sentence as though it is solely based on work from the Middlesex Divorce Research Group, but this section of the SJC report cites four different studies that each found comparable results.

(2) Rosenthal ignores what the SJC is saying about the statistic. After ignoring all other studies mentioned in the report and that exist elsewhere, Rosenthal claims to track down a single study's researcher and says,

The study's author has told me that the data do not demonstrate the court's preference for one parent over the other in custody requests, and that the research was not designed to address the question of how frequently a parent's request was honored.11 So we start off with the author of the study essentially saying that the data cannot be used to support the SJC-GBC's claims. [emphasis retained, not added]

But here is what the SJC actually claims about the statistic:

The high success rate of fathers does not by itself establish gender bias against women.

It was explicitly never meant to prove bias, so Rosenthal has not uncovered some great "gotcha" here. He only managed to show us how poorly he understood the SJC report.

The 70% stat is in the SJC report because the commission was "refuting complaints" from a father's rights group which claimed "mothers are awarded physical custody over 90% of the time." Although dads getting 70% of requested custody isn't proof of bias, it does speak against this father's rights claim. The SJC supports its findings of bias against moms elsewhere, and in great detail, in this lengthy report.

(3) Rosenthal has no data, but he must lie discredit By his own admission,

I have so far been unable to get the raw data. Nowhere in the SJC-GBC’s report is there any indication that the MDRG study’s authors made the raw data available to them.

Though the SJC report doesn't explicitly say "we have data" their descriptions of the data include details that require it, details Rosenthal bemoans he doesn't have. He particularly needs a more detailed breakdown of "joint custody" cases (legal or physical custody? which parent received primary custody). While SJC says ...

Joint physical and joint legal custody was awarded in 3.5% of cases. In 11% of the cases, mothers received primary physical and joint legal custody;

... None of this is visible from Rosenthal's admittedly limited data. He is forced to admit he is actually unable to calculate the desired rates of custody awards from what he has,

How can we calculate the comparable number for maternal custody awards? Unfortunately, from the data available, we can't. As explained above, maternal sole physical custody can be inferred from the maternal sole legal custody column, but no such inference can be made regarding joint physical custody. Lacking that, the following analysis is the best that can be done. Instead he tries to calculate a range of rates, but only for moms, who he concludes receive custody 73.8 to 95% of the time.

This method inflates the rate of custody awards. Yet somehow he forgets to apply the same method when calculating dads' rates, which would be as high as 84.8% if he had, not as notably different from moms' rates.

Also noteworthy, he is measuring only primary physical custody, even in cases where joint custody was awarded. This is not what the SJC report mentioned, but he's hoping to prove he can twist the data to fit any conclusion. It's not clear at all why rates of primary physical custody should be taken as evidence of bias. Rosenthal just says this is the "obvious place" to look for bias (while ignoring legal custody rates or joint physical custody rates because...?). But that measure doesn't control for other variables like who was the primary caregiver, who had domestic abuse or other convictions, who had the most income/resources for the child, etc. Likely that's a big reason the SJC and original researcher both emphasize it's not evidence of bias.

So Rosenthal admittedly lacks any data to speak to bias at all. And he lacks the specific data he hopes will look like (despite not proving) bias against men. Instead he makes up his own numbers with an inconsistent method (and some math errors to boot). All to refute a claim the original report never made, meanwhile ignoring the huge body of evidence finding bias against women.