You may have thought the headline number from last week's report on the U.S. economy was its weak overall growth in the first quarter of this year (0.1% at an annual rate). But for health economists, the big news was the huge surge in household healthcare spending. That popped at an annual rate of 9.9%, the sharpest growth since 1980. It makes obvious sense to attribute the surge to the Affordable Care Act, which kicked into full gear in the January-March period measured by the Bureau of Economic Analysis figures. Yet healthcare experts are pondering the figure with suspicion and perplexity.