The RDA is a scheme that applies to non-wage costs for research & development (the R&D Allowance). If you are investing in equipment or making costs directly linked to your R&D projects, you can make use of this R&D deduction program. The RDA is meant to support Dutch tax-paying (corporate tax and/or income tax) companies which conduct research and development and have an R&D declaration (WBSO).
The RDA covers 40% RDA costs and expenses, or 40 % of the flat rate amount based on the approved R&D hours. By 25% corporate tax, it means 10% net benefit.
The eligible RDA costs and expenses should directly attributable for the R&D work, e.g. costs of building a prototype or raw material costs for doing tests. The eligible expenses are in many cases related to the purchase of assets which are amortized, purchase of other equipment which is directly needed for the R&D work, or investment into research facilities.