Rigorous Analysis of AI Investment Impact on Firm Productivity in Japan
AI investment shows significant positive effects starting 2 quarters after implementation, with peak impact at 3-4 quarters. The causal effect builds gradually, suggesting firms need time to realize AI's full potential.
Event Time | Coefficient | Std Error | T-Statistic | Significance |
---|
The DID estimator shows a 2.4% causal effect of AI investment on quarterly productivity growth. This represents the cleanest estimate of AI's productivity impact, controlling for both firm-specific characteristics and common time trends.
Group | Treatment Effect | Std Error | N Treated | Significance |
---|
Large enterprises show 5.2x higher productivity gains from AI investment compared to SMEs, suggesting significant scale economies in AI implementation. This finding has crucial implications for policy design and business strategy.
IV estimate (0.028) is higher than OLS (0.021), suggesting negative selection bias in AI adoption decisions. Less productive firms may be more likely to adopt AI as a catch-up strategy.
No significant effects detected for fictitious treatment dates, strongly supporting the causal interpretation of our main results. The true treatment effect stands out clearly from the noise.
Specification | Coefficient | 95% CI Lower | 95% CI Upper | Robust |
---|---|---|---|---|
Baseline | 0.024 | 0.018 | 0.031 | โ |
Alternative Controls | 0.026 | 0.019 | 0.033 | โ |
Trimmed Sample | 0.022 | 0.016 | 0.029 | โ |
Bootstrap SE | 0.024 | 0.017 | 0.032 | โ |
Alternative Clustering | 0.025 | 0.018 | 0.032 | โ |
All robustness checks confirm the main finding: AI investment causally improves firm productivity by approximately 2.4% per quarter. The effect is remarkably stable across different specifications, sample restrictions, and estimation methods, providing strong evidence for the causal interpretation.