“…See, for example, Dimatteo et al (2001), Hennerfeind (2006), Sharef et al (2010), Xing et al (2012) and Nasri et al (2013). In addition, a prior based on a Gamma process is devised for monotonically increasing time-varying coefficients, which have been frequently used as an alternative to constant coefficients (Gill & Schumacher, 1987;Deshpande & Sengupta, 1995;Kim et al, 2011). Moreover, monotonically increasing time-varying coefficients are used to assess the existence of waning of treatment effect (Durham et al, 1998).…”