Reinforced block designs with standards

Our aim is to present some new procedures for constructing the reinforced block designs introduced by Das (1958). This work contributes to the theory of connected block designs supplemented by one or more additional treatments and blocks. Such designs are widely used in practice, particularly in agriculture and medicine, where one or more additional treatments called control or standard treatments are often introduced. The basic and additional treatments are replicated in such a way that the requirement of constant number of replications is preserved for both groups of treatments. The reinforced block designs are discussed from the point of view of the properties of so-called information matrix C. The spectral form of C is used.