Power BI Specialist

Location: Hybrid role based in South Wales Contract Length: Initial 3-6 months (extension likely) Day Rate: £400 per day (Outside IR35) Role Overview We are seeking an experienced Power BI Specialist contractor to own enterprise semantic modelling, advanced DAX development and reporting governance.This is a hands-on technical role focused on Power BI semantic models, not dashboard production. You will design, optimise and govern certified enterprise datasets built on the Gold data layer, enabling analysts to self-serve confidently while protecting core business logic. Key Responsibilities Enterprise Semantic Modelling • Design, build and maintain enterprise Power BI semantic models using star schema and dimensional modelling best practice. • Develop advanced DAX measures, calculation groups and reusable logic • Ensure datasets reflect authoritative, agreed business definitions • Implement time-aware models, surrogate keys and conformed dimensions Performance & Optimisation • Diagnose and resolve performance issues across large and complex models • Optimise models through: • Measure refactoring • Cardinality reduction • Relationship and filter-direction optimisation • Advise on Import, DirectQuery and Composite storage strategies Governance & Hybrid Model Operation • Certify and endorse enterprise semantic models • Enforce separation between certified datasets and exploratory/self-service reporting • Prevent duplication of KPIs, measures and business logic • Define and embed dataset lifecycle and workspace standards What you need to do now If you're interested in this role, click 'apply now' to forward an up-to-date copy of your CV, or call us now.If this job isn't quite right for you, but you are looking for a new position, please contact us for a confidential discussion about your career. Hays Specialist Recruitment Limited acts as an employment agency for permanent recruitment and employment business for the supply of temporary workers. By applying for this job you accept the T&C's, Privacy Policy and Disclaimers which can be found at hays.co.uk