The claim is that traditional [[object-oriented programming]] (OOP) design principles result in poor data locality,{{Clarify|reason=What?Sorry, but OOP doesn't have to do anything with data layouts or design<ref>https://www. Data are instances of the Objects and can be organized irrelevantly to OOP itselfintel. The whole paragraph make no sensecom/content/dam/www/public/us/en/documents/presentation/improving-vectorization-efficiency.|date=September 2021}}pdf</ref><ref>https://arxiv.org/pdf/1710.03462.pdf</ref>, more so if runtime polymorphism ([[dynamic dispatch]]) is used (which is especially problematic on some processors).<ref>{{cite web|title=What's wrong with Object-Oriented Design? Where's the harm in it?|url=http://www.dataorienteddesign.com/dodmain/node17.html}}describes the problems with virtual function calls, e.g., i-cache misses</ref><ref>{{cite web|title=Data-oriented design - why you might be shooting yourself in the foot with OOP|url=http://gamesfromwithin.com/data-oriented-design}}</ref> Although OOP appears to "organise code around data", it actually organises [[source code]] around [[data type]]s rather than physically grouping individual fields and arrays in an efficient format for access by specific functions. Moreover, it often hides layout details under [[abstraction layer]]s, while a data-oriented programmer wants to consider this first and foremost.
