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KiwiSaver: Comparing Survey and Administrative Data

Publication Details

  • KiwiSaver: Comparing Survey and Administrative Data
  • Published: 18 Feb 2014
  • Status: Current
  • Authors: Law, David; Samoilenko, Anton
  • Pages: (2),i-iv,1-39
  • ISBN: 978-0-478-42120-0 (Online)
  • Ref. No: WP 14/06
  • Pub. type: Working Papers
  • JEL Classification: D91; E21

KiwiSaver: Comparing Survey and Administrative Data

Published 18 February 2014

Author: Anton Samoilenko and David Law


This paper explores the KiwiSaver information contained in two sources: the administrative data from the Inland Revenue Department (IRD) and the Survey of Family, Income and Employment (SoFIE). In particular, the paper explores the membership and contribution information, explaining significant patterns and highlighting any differences that exist between the two data sources. At the aggregate level, the paper shows noticeable difference in membership levels, tenure, annual employer and employee contributions and total cumulative contributions. At the individual level, regression results identify the main determinants of the observed differences and quantify their impact.

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Executive Summary

1 Introduction

2 Data

3 IRD administrative dataset

4 SoFIE dataset

5 Key points of difference

6 Analysis of differences

7 Discussion and conclusion


twp14-06.pdf (708 KB) pp. (2),i-iv,1-39


Authors would like to acknowledge the helpful comments from Katherine Meerman, Malcolm Menzies, Kristie Carter, Barb Lash and Ian McGregor.


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.

Access to the data used in this study was provided by Statistics New Zealand under conditions designed to give effect to the security and confidentiality provisions of the Statistics Act 1975.

The results presented in this study are the work of the author, not Statistics New Zealand.

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