Related Experiment Video
Updated: Apr 7, 2026

Novel Object Recognition and Object Location Behavioral Testing in Mice on a Budget
Published on: November 20, 2018
Global tests for novelty
Ilmari Ahonen1,2, Denis Larocque3, Jaakko Nevalainen1,4
11 Department of Mathematics and Statistics, University of Turku, Finland.
Abstract:
Outlier detection covers the wide range of methods aiming at identifying observations that are considered unusual. Novelty detection, on the other hand, seeks observations among newly generated test data that are exceptional compared with previously observed training data. In many applications, the general existence of novelty is of more interest than identifying the individual novel observations. For instance, in high-throughput cancer treatment screening experiments, it is meaningful to test whether any new treatment effects are seen compared with existing compounds. Here, we present hypothesis tests for such global level novelty. The problem is approached through a set of very general assumptions, making it innovative in relation to the current literature. We introduce test statistics capable of detecting novelty. They operate on local neighborhoods and their null distribution is obtained by the permutation principle. We show that they are valid and able to find different types of novelty, e.g. location and scale alternatives. The performance of the methods is assessed with simulations and with applications to real data sets.
Insights
This study introduces novel hypothesis tests for global novelty detection, identifying exceptional patterns in new data. These methods are validated for detecting various novelty types in real-world applications.
Area of Science:
- Statistics
- Machine Learning
- Bioinformatics
Background:
- Outlier detection identifies unusual observations, while novelty detection finds exceptional new data points compared to training data.
- Often, the presence of novelty itself is more critical than pinpointing individual novel instances, such as in screening new cancer treatments.
Purpose of the Study:
- To develop and validate hypothesis tests for global level novelty detection.
- To introduce innovative methods applicable under general assumptions, advancing current literature.
Main Methods:
- Development of novel test statistics operating on local neighborhoods.
- Utilizing the permutation principle to derive the null distribution of the test statistics.
- Assessing method validity and performance through simulations and real-world data analysis.
Main Results:
- The proposed tests are shown to be valid for detecting novelty.
- The methods successfully identify different types of novelty, including location and scale alternatives.
- Performance evaluation confirms the efficacy of the developed novelty detection techniques.
Conclusions:
- The presented hypothesis tests offer a robust approach to global novelty detection.
- These methods provide a valuable tool for applications where identifying the existence of new patterns is crucial.
- The innovative framework broadens the scope of novelty detection methodologies.
Related Concept Videos
Types of Hypothesis Testing
When the null and alternative hypotheses are stated, it is observed that the null hypothesis is a neutral statement against which the alternative hypothesis is tested. The alternative hypothesis is a claim that instead has a certain direction. If the null hypothesis claims that p = 0.5, the alternative hypothesis would be an opposing statement to this and can be put either p > 0.5, p < 0.5, or p...
Significance Testing: Overview
Multiple Comparison Tests
It would be easy to compare two samples using a significance alpha level of 0.05. In other words, there is only one sample pair to be compared. However, it would be difficult to identify a significantly different sample if the number...
Sign Test for Nominal Data
For example, consider a...
Test for Homogeneity
Introduction to Test of Independence
The test statistic for a test of independence is similar to that of a goodness-of-fit test:

