Many European countries have abolished mandatory audits for small firms to reduce their regulatory burden. In a recent article, Dong et al. (2023) reported that voluntarily audited firms experienced a 19% reduction in their total tax burden compared to mandatorily audited firms following an auditing reform in Sweden, suggesting a causal link between the revised auditing regulation and corporate tax avoidance. In this study, we first replicate Dong et al.’s (2023) results with reasonable accuracy. We then incorporate a series of placebo tests to examine whether their results are causal effects of the reform or spurious correlations. Placebo tests adjusting the timing of the reform, along with tests modifying the size of firms eligible for voluntary audits under the reform, reveal statistically significant reform effects where none should be expected. To further investigate, we conduct an independent analysis of the data, finding that voluntarily audited firms increased their tax payments due to the introduction of the reform, rather than reducing them.