And without access to any of the statistical calculations made by the U.N. for either estimates, scholars cannot independently replicate the findings of the U.N. for either of its 2017 or 2022 reports.

This lack of transparency makes it difficult to claim that there really was an increase of 10 million in the number of enslaved persons from 2017 to 2022.

Two things are happening here. The U.N. seems to be getting much better at estimating global slavery. But because the survey techniques are improving over time, it is impossible to make comparisons.

Consider the analogy of a bathroom scale. In weighing yourself, you might purchase an inexpensive scale at first just to get a rough idea of how much you weigh. But then, becoming more concerned about your health, you then purchase a much better scale that gives you a far more precise measurement.

This doesn’t mean that your weight changed radically. It just means you now have a much better sense of your weight.

This analogy applies to measuring contemporary slavery.

The scale used by Walk Free was novel in 2013, and improved by 2016. The scale the U.N. used in 2017 was more precise, and the figures for 2022 got even better.

But to go back and say there are 10 million more persons enslaved today than there were in 2017 is not warranted.

Global estimates of modern slavery are eye-catching and important.

The 50 million figure today is one of the best estimates of modern slavery available and can prompt policymakers to take action. Without awareness of this crime, the problem cannot be solved.

Yet, moving forward, the public still needs more reliable, more valid and more transparent data. Science advances on the promise that data is freely available to enable others to replicate or improve the analysis.

This article is republished from The Conversation, an independent nonprofit news site dedicated to sharing ideas from academic experts. It was written by: Monti Datta, University of Richmond. Like this article? subscribe to our weekly newsletter.

Read more:
Slavery is not a crime in almost half the countries of the world – new research

Slavery was never abolished – it affects millions, and you may be funding it

Monti Datta was a consultant with the Walk Free Foundation from 2013 to 2016.