The computation of first-differences by firm involves sorting by field (zd), firm (org_new), and year, but neglects city (bea). Consequently, DD1 represents a first-difference across urban areas.
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Escalating fuel costs are intensifying financial strain on American families, particularly affecting those with moderate incomes who have limited capacity to manage increased transportation expenditures. These price hikes can alter driving patterns, vacation plans, and discretionary spending.
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