The Investment in Training survey is a follow-up survey to the Employer Skills Survey, looking more specifically at training that employers provide for their employees, and how much employers invest in this. This publication is a supplement to the Employer Skills Survey 2015 report, and presents training expenditure figures, by country, broken down into its constituent elements. It also tracks training expenditure figures over time, incorporating findings from the 2011 and 2013 Investment in Training surveys. It is worth noting that for the 2015 data, a new weighting strategy was implemented to improve the accuracy of the training spend estimates. This new weighting strategy was also retrospectively applied to both the 2011 and 2013 data files. Readers who are familiar with the Investment in Training 2011 and 2013 reports will therefore find that the historical figures presented here do not exactly match those previously presented. A technical annex contains a more detailed explanation of the revised weighting strategy, analysis of its effectiveness, and impact on training spend.