These statistics are hard to calculate. Defining “actively searching for work” is one way. You have to draw a line in the sand somewhere. For example, say I’m the primary breadwinner and my wife works part time at a restaurant and cares for our daughter in the remaining time. Work goes slow and she gets laid off. She could actively try to find another job but decides to spend full time with our daughter instead. I don’t know that she’s “hopeless” but rather made a different choice. Certainly there are hopeless people. It’s hard to find a perfect measure.
It is difficult to define "actively searching for work" with a consistent baseline across the decades, but it is not all that difficult to arrive at a definition that is valid for any given point of time. Simply consider the social norms for the era. If it is considered normal to have two income households at any given point of time, then it is legitimate to include an unemployed spouse.
Another route, similar to the one in this study, may be considering people who are actively searching for work and where the household income is below a certain threshold (likely based upon the composition of the family).
Yeah, that's one of the reasons why I suggested a hybrid of seeking employment and household income. It is similar to the one used by the study, except the article seems to use individual income rather than household income. Of course, there are still problems with that approach. For example: a baseline household income makes many assumptions about a decent standard of living, it would also be complicated to calculate due to variations in household size/composition and regional differences in the cost of living.
That being said, "seeking employment" is likely one of the worse indications of unemployment. People may be excluded or impeded from joining the workforce for a variety of reasons and stop seeking employment because of that. It is a rather long list: discrimination (age, disability, gender, race), accommodations for disabilities, access to affordable childcare, criminal record, level of education. While some of those can be addressed, they rarely are addressed in a meaningful manner. In those cases I find it difficult to treat not-seeking employment as a choice.
