International Trade & Competitiveness Analytics
Grubel-Lloyd Intra-Industry Trade & Balassa RCA Formula
Distinguish two-way variety trade via Grubel-Lloyd Index GL_i = 1 - ABS(X_i - M_i)/(X_i + M_i) from inter-industry specialization via Bela Balassa’s (1965) Revealed Comparative Advantage RCA_ij.
Separate Krugman two-way variety trade (Grubel-Lloyd) from Ricardian specialization (Balassa RCA)!
Trade economists diagnose industrial competitiveness with two complementary bilateral/sectoral indices. First, Herbert Grubel and Peter Lloyd (1975) measured Intra-Industry Trade (simultaneous exports X_i and imports M_i within the SAME HS/SITC product category, e.g., Germany exporting and importing automobiles) via GL_i = 1 - ABS(X_i - M_i) / (X_i + M_i) = (2 * MIN(X_i, M_i)) / (X_i + M_i) in [0, 1] (where GL_i = 1 is pure balanced two-way trade and GL_i = 0 is pure one-way inter-industry trade)! Second, Bela Balassa (1965) measured Revealed Comparative Advantage via RCA_ij = (X_ij / X_i_tot) / (X_w_j / X_w_tot) — Country i’s export share in sector j divided by the World’s export share in sector j (RCA > 1.00 signals comparative advantage; symmetric log-normalized RSCA = (RCA - 1) / (RCA + 1) maps [0, inf) cleanly onto [-1, +1])!
Verify on Country_Sector_Exports X_ij = 60.0 ($B, B2), Country_Sector_Imports M_ij = 40.0 ($B, B3), Country_Total_Exports X_i_tot = 400.0 ($B, B4), World_Sector_Exports X_w_j = 1,500.0 ($B, B5), and World_Total_Exports X_w_tot = 20,000.0 ($B, B6): Grubel-Lloyd Index is 1 - ABS(60 - 40) / 100 = 0.8000 (80.0% two-way intra-industry overlap!); Country Export Share is 60 / 400 = 0.1500 (15.0%) vs World Share 1,500 / 20,000 = 0.0750 (7.5%), giving Balassa RCA = 0.1500 / 0.0750 = 2.0000 (> 1 -> strong comparative advantage!) and Symmetric Laursen RSCA = (2 - 1) / (2 + 1) = 0.3333!
| Trade Specialization Metric (X=60, M=40, X_tot=400, X_wj=1.5T, X_wtot=20T) | Formula | Verified Output |
|---|---|---|
| Grubel-Lloyd Intra-Industry Index (GL) | 1 - ABS(X - M) / (X + M) | 0.8000 (80.0% Two-Way Trade) |
| Country vs World Export Shares | (60 / 400) vs (1,500 / 20,000) | 15.00% vs 7.50% |
| Balassa Revealed Comparative Advantage | (X_ij / X_tot) / (X_wj / X_wtot) | 2.0000 (> 1.00 Advantage!) |
| Laursen Symmetric RSCA Index | (RCA - 1) / (RCA + 1) | 0.3333 (Bounded in [-1, +1]) |
Grubel-Lloyd (1975) Intra-Industry Trade Index Formula
Guard zero gross sectoral trade X_i + M_i = 0 cleanly.
=IF(OR(B2 < 0, B3 < 0, B2 + B3 <= 0), "No Sector Trade", ROUND(1 - ABS(B2 - B3) / (B2 + B3), 4))Balassa (1965) Revealed Comparative Advantage & Symmetric RSCA Formula
Validate 0 <= X_ij <= X_i_tot, X_i_tot > 0, and 0 < X_w_j <= X_w_tot.
=LET(x_ij, B2, x_it, B4, x_wj, B5, x_wt, B6, IF(OR(x_ij < 0, x_it <= 0, x_ij > x_it, x_wj <= 0, x_wt <= 0, x_wj > x_wt), "Invalid Trade Totals", ROUND((x_ij / x_it) / (x_wj / x_wt), 4)))Try the example
Use the original values or change them to test your understanding.