########################################################################

# Change point models.

######################################################################

model

{

for( year in 1 : N )

{

D[year] ~ dpois(mu[year])

log(mu[year]) <- b[1] + step(year - changeyear) * b[2]

}

b[1] ~ dnorm( 0.0,1.0E-6)

b[2] ~ dnorm( 0.0,1.0E-6)

for( year in 1 : N ) { p[year] <- 1/N }

changeyear ~ dcat(p[])

}

# Initial values

list(b = c(0, 0), changeyear = 50)

# Data 1

list( N = 112, D=c(4,5,4,1,0,4,3,4,0,6,

3,3,4,0,2,6,3,3,5,4,5,3,1,4,4,1,5,5,3,4,2,5,2,2,3,4,2,1,3,2,

1,1,1,1,1,3,0,0,1,0,1,1,0,0,3,1,0,3,2,2,

0,1,1,1,0,1,0,1,0,0,0,2,1,0,0,0,1,1,0,2,

2,3,1,1,2,1,1,1,1,2,4,2,0,0,0,1,4,0,0,0,

1,0,0,0,0,0,1,0,0,1,0,0)

)

# D[t] ~ POI(mu1) fot t < changeyear

# D[t] ~ POI(mu2) fot t >= changeyear