This paper presents an approach to monitoring and predicting the trustworthiness of services that are assembled from component services. In service compositions the number of component services that need to be aggregated may be large and dynamically changing. Additionally, the component services may vary in their importance to the value of the composite service and in their trustworthiness and resource capacity. Service compositions require the capability to dynamically adapt to changes that may occur at runtime. Those changes can occur in supply and demand, in the environment or in the component services' properties and behaviour. Service composers need to be able to respond swiftly to changed trustworthiness requirements and capabilities of service compositions, where those changes may not be easily predictable. With the availability of alternatives providing the same functionality as those already integrated in a composition, service composers can take advantage of this by replacing degrading or unsatisfactory components.