Steady-state fusion devices, such as Wendelstein 7-X, require new approaches for data analysis. These efforts are motivated by both the physics and the technical requirements of steady-state operation. Diagnostic data and physics information, such as modeling results, are linked to arrive at an integrated data analysis. For this purpose, methods of Bayesian probability theory are employed. The analysis of Thomson scattering data is discussed. Capabilities for assessing diagnostic setups are outlined. Extension to more complex analyses are presented. Technical issues resulting from desired on-line capabilities are discussed.