where official income statistics changed little. Some analysts interpreted the lights as evidence of unrecorded economic growth. Field surveys found, however, that a rural electrification program had recently replaced dim household lamps with bright streetlights, while many businesses still operated at the same scale. Researchers are trying to determine when additional light reflects more economic activity and when it merely reflects a change in lighting technology or public infrastructure. Which of the following best states the primary problem explored in the passage without broadening or narrowing its scope?