The trend started a decade ago, or even earlier, about the time when social media took over and many elite newsrooms began caring less about seeking out qualified, informed voices on both sides of hot stories.

The result was a kind of fail-safe method for spotting media bias, especially with stories located at the intersection of politics, religion and the cultural changes, especially those linked to the Sexual Revolution.

First, readers can print a copy of the story in question and then, with a highlighter pen, mark quotes from people who appear to have been interviewed by the reporters — the sources whose voices provide the framing anecdotes and quotations that provide crucial facts and material that interpret the facts.

Then, with a second highlighter, mark the quotes from experts, activists and citizens on the other side of the issue. The key question: How many of these quotes came from actual interviews and how many were taken from online press releases and statements?

Compare and contrast. The big question: What sources were shown respect — with personal interviews — and which sources were demoted to PR release status? (Personal comment: As a columnist, I have found that quoting personal weblogs — Twitter as well — can offer a kind of neutral ground, with more information and authentic “voices” than mere press releases.)

In my experience, 99% of the time the people who are quoted from interviews represent the viewpoints that are favored and respected by the journalists who produced the story. With that in mind, let’s look at the sourcing in an international-desk story that ran in The Washington Post with this headline: “Mexico decriminalizes abortion, a dramatic step in world’s second-biggest Catholic country.”

The Catholic angle is crucial, of course. Who would be interviewed? Activists in ministries to pregnant women? Canon lawyers? Perhaps a Catholic priest or historian who knows why “life” issues are so crucial in the church’s theology? I will also ask: Was anyone from the religion-desk allowed input into the sourcing?

Let’s start with the overture:

MEXICO CITY — Mexico’s supreme court voted Tuesday to decriminalize abortion, a striking step in a country with one of the world’s largest Catholic populations and a decision that contrasts with tighter restrictions introduced across the border in Texas.