A maximum-mean-discrepancy goodness-of-fit test for censored data

We introduce a kernel-based goodness-of-fit test for censored data, where observations may be missing in random time intervals: a common occurrence in clinical trials and industrial life-testing. The test statistic is straightforward to compute, as is the test threshold, and we establish consistency under the null. Unlike earlier approaches such as the Log-rank test, we make no assumptions as to how the data distribution might differ from the null, and our test has power against a very rich class of alternatives. In experiments, our test outperforms competing approaches for periodic and Weibull hazard functions (where risks are time dependent), and does not show the failure modes of tests that rely on user-defined features. Moreover, in cases where classical tests are provably most powerful, our test performs almost as well, while being more general

A Kernel Independence Test for Random Processes

A new non parametric approach to the problem of testing the independence of two random process is developed. The test statistic is the Hilbert Schmidt Independence Criterion (HSIC), which was used previously in testing independence for i.i.d pairs of variables. The asymptotic behaviour of HSIC is established when computed from samples drawn from random processes. It is shown that earlier bootstrap procedures which worked in the i.i.d. case will fail for random processes, and an alternative consistent estimate of the p-values is proposed. Tests on artificial data and real-world Forex data indicate that the new test procedure discovers dependence which is missed by linear approaches, while the earlier bootstrap procedure returns an elevated number of false positives. The code is available online: https://github.com/kacperChwialkowski/HSIC .Comment: In Proceedings of The 31st International Conference on Machine Learnin

Firm size and export performance: some empirical evidence

This paper uses firm level data collected by the Australian Bureau of Statistics in its Business Longitudinal Survey to help fill the information gap about the characteristics of successful exporters. This study suggests that the main influences on export performance of Australian manufacturing firms may lie with a range of ‘firm-specific’ factors other than size or domestic market share. These potentially include: kind of activity, product design and quality, marketing expertise and the motivation of management.firm size - exports - performance - business - company - exporters

Land degradation: links to agricultural output and profitability

To understand land degradation and assess policy responses, knowledge is needed of the bio-physical causes, the economic effects on farms and the incentives farmers face to avoid or ameliorate the degradation. An empirical study of land degradation in the Australian state of New South Wales is presented in this article. The results suggest that there are incentives for farmers to co-exist with certain forms of degradation, while there are also incentives to avoid some other forms.Land Economics/Use,