Lists after a colon
A list that follows a colon should always have parallel elements.
Not parallel
Mainstream economists have attributed the recession to several key causes: deregulation policies, spike in interest rates, manufacturing orders declining, and the emergence of asset bubbles.
Parallel
Mainstream economists have attributed the recession to several key causes: the enactment of deregulation policies, the spike in interest rates, the decline in manufacturing orders, and the emergence of asset bubbles.
Mainstream economists have attributed the recession to several key causes: deregulation policies, high interest rates, low manufacturing orders, and asset bubbles.