Metric Facts
Fast-food jobs after New Jersey's 1992 minimum-wage rise · provisional
Headline
more full-time-equivalent workers per New Jersey restaurant than the Pennsylvania trend predicts+2.75
more full-time-equivalent workers per New Jersey restaurant than the Pennsylvania trend predicts+2.75
Plausible range +0.09 to +5.42 · As published (t statistic), method not stated
We counted staff at fast-food restaurants in early 1992 and again late in the year. New Jersey raised its minimum wage on 1 April; nearby Pennsylvania did not. We compare how the average staff per restaurant changed in each state.
CountedRestaurants who: fast-food restaurants in New Jersey and eastern Pennsylvania from four chains that took part in the first telephone survey; reported staff numbers in that survey round Each round's average uses every restaurant with a count for that round, so the two rounds are not exactly the same restaurants; restaurants that closed for good by the second round count as having zero staff The four that were closed only temporarily are left out of the second round. n = 410
Clock startsNew Jersey's minimum wage went from $4.25 to $5.05 an hour on 1 April 1992.
First survey roundDays −46 to −28 (observation). The telephone survey from 15 February to 4 March 1992, before the rise.
Second survey roundDays 218–274 (outcome). The follow-up survey from 5 November to 31 December 1992, about 7 to 9 months after the rise.
What countsThe same count, taken in the second survey round.
Combined asAverage the staff count over restaurants in each state and survey round.
Compared byTake New Jersey's change in average staff between the two rounds. Subtract Pennsylvania's change over the same months. What is left is the change Pennsylvania's path does not explain.
(NJ₂ − NJ₁) − (PA₂ − PA₁) · ATTKind of claimPoints toward a cause, with assumptions. The design removes some alternative explanations, not all. Read it as a cause only if its assumptions hold.
CompletenessThe latest wage rise is 01 Apr 1992; its second survey round ends 31 Dec 1992. Data are complete through 31 Dec 1992, so every window is fully observed. This number should not move as more data arrive.
Before you repeat it
Pennsylvania staffing fell over the year, so most of the gap comes from Pennsylvania shrinking, not New Jersey growing. The design assumes both states would otherwise have moved alike, and the interval's width depends on a calculation the paper does not describe.
Caveats
- ◎Pennsylvania fell more than New Jersey rose
- ±The spread depends on an unstated calculation
- ±Self-reported counts from a phone survey
- ◎One region, one industry, one rise
Don't say
- Each New Jersey restaurant hired 2.75 more people.
- This proves minimum-wage rises create jobs.
- Employment rose 13%.
5 known gap(s) between description and code: Store identifier; Where closed stores become zero; Headline value; How the headline's uncertainty was computed; Restaurants without a starting wage.
↑ may overstate · ↓ may understate · ± uncertainty understated · ↕ either way · ◎ limits scope. Owner: data-visual-explainer worked example (public data). Updated 2026-10-07. Data as of 1994-09 (published); recomputed 2026-10-07. Sources: S1 njmin-aer.pdf, S2 check.sas, S3 codebook, S4 read.me, S5 analysis.py, S6 public.dat.