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Decomposing New Zealand's Terms of Trade

Publication Details

  • Decomposing New Zealand's Terms of Trade (WP 15/16)
  • Published: 8 Dec 2015
  • Status: Current
  • Author: Mellor, Phillip
  • Pages: (2),iv,37
  • ISBN: 978-0-908337-38-5 (Online)
  • Ref. No: WP 15/16
  • Pub. type: Working Papers
  • JEL Classification: E30; F10; F14; F17

Decomposing New Zealand's Terms of Trade

Published 8 Dec 2015

Author: Phillip Mellor


This paper adds to the understanding of how New Zealand's terms of trade have evolved since 1991. The paper develops a method to decompose the percentage change in the terms of trade into the contributions from different export and import components. The contributions are further decomposed into the contributions attributable to changes in deflators (prices) and contributions from changes in the composition of the export and import baskets. The methodology can be applied to a variety of timeframes to assess the drivers of short and long term fluctuations in the terms of trade. Three key insights emerge from applying the decomposition to New Zealand. Firstly, the decomposition supports the view that increasing export prices have made the largest contribution to gains in the terms of trade over the past two decades. Secondly, the change in the composition of the import basket is shown to have made a material positive contribution to gains in the terms of trade. Import prices have been a drag on the terms of trade over longer timeframes, although in recent years they have made a positive contribution. Finally the paper does not find a material impact from the change in the composition of exports over time.


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Executive Summary

1 Introduction

2 External Sector Background

3 Methodology

4 Findings

5 Conclusion


Appendix One - Mathematical Derivation of the Terms of Trade Decomposition

Appendix Two - Component Decomposition Charts

Appendix Three - Comparisons to the 1995/96 Base Year

twp15-16.pdf (724 KB) pp. (2),iv,1–37


I am grateful to Philip Borkin, Patrick Conway, Michael Johnston, and Michael Reddell for comments on an earlier draft of this paper. I would also like to acknowledge the support of the Treasury Forecasting team.


The views, opinions, findings, and conclusions or recommendations expressed in this Working Paper are strictly those of the author(s). They do not necessarily reflect the views of the New Zealand Treasury or the New Zealand Government. The New Zealand Treasury and the New Zealand Government take no responsibility for any errors or omissions in, or for the correctness of, the information contained in these working papers. The paper is presented not as policy, but with a view to inform and stimulate wider debate.

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