Abstract
An important stylized fact in the literature is that more Workers’ Compensation claims for difficult-to-diagnose injuries are filed on Monday than on any other day of the week. This paper studies the impact of recreational marijuana sales legalization on Monday work injury claims. Using restricted-use Workers’ Compensation claim data in Oregon and a Difference-in-Differences (DiD) model, I find the probability of overall Monday injuries increase by 4 percentage points after recreational marijuana sales legalization. The event study graphs suggest the medium-term effects appear to equal the short-term effects. Additionally, I do not find strong evidence to support those difficult-to-diagnose Monday injuries disproportionately increase after recreational marijuana sales legalization, suggesting a limited moral hazard of Monday injury claiming behavior after recreational marijuana sales legalization.
Acknowledgement
I thank Gary Engelhardt, Jeffrey Kubik, and Ross Jestrab for their helpful comments. I also thank the editor and the anonymous referee for their valuable suggestions. I appreciate the assistance of the Oregon Department of Consumer and Business Services, Oregon Workers’ Compensation Department, and Oregon Liquor Control Commission for their data support. The statements, findings, conclusions, views, and opinions contained and expressed herein are not necessarily those of Oregon Workers’ Compensation Department, Oregon Occupational Safety and Health Administration or any of their affiliated or subsidiary entities. All errors are my own.
Summary statistics on claim numbers over time and weekdays.
| Year | Monday | Tuesday | Wednesday | Thursday | Friday |
|---|---|---|---|---|---|
| 2013 | 1916 | 1826 | 1741 | 1722 | 1765 |
| 2014 | 1924 | 1774 | 1816 | 1825 | 1733 |
| 2015 | 1992 | 1896 | 1749 | 1846 | 1661 |
| 2016 | 2030 | 2011 | 1969 | 1908 | 1873 |
| 2017 | 2024 | 1961 | 1899 | 1992 | 1902 |
-
The table reports the claim numbers by each day-of-the-week from 2013 to 2017.
The effect of recreational marijuana sales legalization on number of Monday claim.
| Sample | (1) | (2) | (3) | (4) |
|---|---|---|---|---|
| All injuries | Sprains, strains | Fractures | Cuts, lacerations | |
| Treat*after | 0.410*** | 0.112 | 0.146*** | 0.152** |
| (0.134) | (0.109) | (0.054) | (0.062) | |
| Control mean | 4.468 | 3.197 | 0.464 | 0.807 |
| N | 2160 | 2160 | 2160 | 2160 |
-
The table reports the DiD estimates using county-level analysis, where the dependent variable is the number of Monday claims in county c and month t. Standard errors are two-way clustered at the county and year level in parentheses. * p < 0.10, ** p < 0.05, *** p < 0.01.
Robustness checks: difference-in-difference regression.
| Sample | (1) | (2) | (3) | (4) |
|---|---|---|---|---|
| All injuries | Sprains,strains | Fractures | Cuts,lacerations | |
| Panel A: placebo test | ||||
| Treat*after | −0.012 | 0.009 | −0.118 | 0.019 |
| (0.038) | (0.031) | (0.117) | (0.111) | |
| N | 25,735 | 18,193 | 2931 | 4611 |
| Panel B: dropping small counties | ||||
| Treat*after | 0.038** | 0.042** | 0.029 | 0.046 |
| (0.018) | (0.022) | (0.044) | (0.037) | |
| N | 46,677 | 32,402 | 5507 | 8768 |
| Panel C: dropping border counties | ||||
| Treat*after | 0.035* | 0.043** | 0.027 | 0.027 |
| (0.019) | (0.021) | (0.063) | (0.049) | |
| N | 32,892 | 22,621 | 4076 | 6195 |
-
Panel A reports the placebo test of the DiD estimates in Eq. (1) but defines After = 1 if it is July 2015, which is one quarter before the recreational marijuana sales legalization. Panel A also excludes the post-treatment period (After October 2015) from the original estimation sample. Panel B excludes the 5% less populated counties (i.e. 2000 people) in Oregon into the analysis. Panel C excludes the western Oregon border counties into the analysis. Standard errors are two-way clustered at the county and year level in parentheses. * p < 0.10, ** p < 0.05, *** p < 0.01.
Event study analysis.
| (1) | (2) | (3) | (4) | |
|---|---|---|---|---|
| All injuries | Sprains, strains | Fractures | Cuts, lacerations | |
| −8 | −0.004 | −0.003 | −0.013 | 0.001 |
| (0.011) | (0.013) | (0.023) | (0.018) | |
| −7 | 0.011 | 0.006 | 0.032 | 0.024 |
| (0.010) | (0.011) | (0.030) | (0.024) | |
| −6 | −0.010 | −0.007 | −0.000 | −0.021 |
| (0.008) | (0.011) | (0.033) | (0.020) | |
| −5 | −0.003 | −0.003 | 0.041 | −0.032 |
| (0.012) | (0.014) | (0.025) | (0.023) | |
| −4 | −0.009 | −0.011 | 0.035 | −0.031* |
| (0.010) | (0.010) | (0.032) | (0.019) | |
| −3 | −0.003 | 0.007 | −0.026 | −0.026 |
| (0.009) | (0.010) | (0.027) | (0.022) | |
| −2 | −0.010 | −0.008 | −0.006 | −0.013 |
| (0.008) | (0.010) | (0.028) | (0.012) | |
| 0 | 0.057*** | 0.047* | 0.069 | 0.099** |
| (0.020) | (0.024) | (0.057) | (0.040) | |
| 1 | 0.048** | 0.044* | 0.085 | 0.045 |
| (0.021) | (0.025) | (0.056) | (0.041) | |
| 2 | 0.030 | 0.039 | −0.004 | 0.027 |
| (0.019) | (0.024) | (0.048) | (0.040) | |
| 3 | 0.024 | 0.021 | 0.044 | 0.029 |
| (0.020) | (0.024) | (0.049) | (0.041) | |
| 4 | 0.026 | 0.035 | 0.016 | 0.013 |
| (0.019) | (0.023) | (0.049) | (0.040) | |
| 5 | 0.026 | 0.017 | 0.021 | 0.065 |
| (0.019) | (0.023) | (0.048) | (0.040) | |
| 6 | 0.033* | 0.027 | 0.062 | 0.043 |
| (0.019) | (0.023) | (0.053) | (0.046) | |
| 7 | 0.020 | 0.025 | 0.010 | 0.019 |
| (0.020) | (0.024) | (0.053) | (0.041) | |
| 8 | 0.047** | 0.060** | 0.015 | 0.028 |
| (0.019) | (0.024) | (0.048) | (0.041) | |
| Observations | 46,755 | 32,454 | 5519 | 8782 |
-
The table reports the event study estimates from Eq. (2). The dependent variable in all regression is whether a claim occurred on a Monday or not. Standard errors are two-way clustered at the county and year level in parentheses. * p < 0.10, ** p < 0.05, *** p < 0.01.
Workplace drug positivity rate by drug category and state.
Data is from Quest Diagnostics. The vertical dashed red line is the recreational marijuana law passage year for each western state.
Event study for number of Monday claims models.
The graphs show the event study based on the DiD model as in Table A2. Standard errors are two-way clustered at the county and year level, and the gray bars depict 95% confidence intervals.
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