You should read the materials you linked. They literally fabricated a new economic indicators index to provide a better score than the one previously used.
Where does it say that? Among the metrics they use are unemployment, job openings, and GDP growth. Seems pretty standard to me. The Fed article that discusses a new index isn't 'fabricating' a new index; they developed a way to separate the performance of the metropolitan area from the city proper so good performance for the overall metro area wouldn't give an I correctly rosy picture of the city proper. If you're gonna tell me to read my links, maybe you should make sure you read them first.
Please do quote me exactly where it says this new Detroit-only metric shows the city doing better than the metro-inclusive metric. I'm particularly curious to see where it says that since the article explicitly points out that the Detroit-only index performed worse than the metro-inclusive index.
> Moreover, the city’s economic growth more frequently dropped back into negative territory than the MSA’s:
