This is a serious issue with the Democratic Party right now, they’re relying on metrics and measurements that do not properly reflect the realities of the average voter. It goes beyond just misreading economic numbers, they are struggling to even understand what voters will respond positively to in general.
Many of the questions they ask in polls are somewhat obtuse and don’t touch on what voters think the issue is. They ask “how important is X to you” but be it, immigration, environment, healthcare, or guns. All that question does is tell the party how much to talk about certain issues, not how the voters want them to be addressed or treated.
Decision makers with in the party apparatus have a strategy of working with in narratives that are accepted by the voters they’re trying to court. Narratives crafted and popularized by traditional media/news/journalistic sources. Ideally these narratives would be crafted to best reflect reality, a difficult task that requires a lot of talent and large dedicated staffs. Right now though narratives are being crafted by under staffed, underfunded teams, at the behest of powerful moneyed interests who are keeping news sources afloat; revenues from digital distribution having failed to match that of old print and cable distribution. These same interests provide the bulk of funding for political campaigns.
So narratives are crafted that are divorced from reality the public is experiencing, in a shallow effort to control public opinion, making the public increasingly distrustful over time of these traditional news sources. The party relies on these narratives to communicate with voters. They also takes ques on what policy to support based on how the voters identify with the narratives and what the campaign donors want. But increasingly voters do not identify with the narratives at all, so the party is left speaking past voters trying to speak to narratives that voters ether haven’t seen or are baffled by.