algo.cdc | R Documentation |

Surveillance using the CDC Algorithm

```
algo.cdcLatestTimepoint(disProgObj, timePoint = NULL,
control = list(b = 5, m = 1, alpha=0.025))
algo.cdc(disProgObj, control = list(range = range, b= 5, m=1,
alpha = 0.025))
```

`disProgObj` |
object of class disProg (including the observed and the state chain). |

`timePoint` |
time point which should be evaluated in |

`control` |
control object: |

Using the reference values for calculating an upper limit, alarm is
given if the actual value is bigger than a computed threshold.
`algo.cdc`

calls `algo.cdcLatestTimepoint`

for the values
specified in `range`

and for the system specified in
`control`

. The threshold is calculated from the predictive
distribution, i.e.

`mean(x) + z_{\alpha/2} * sd(x) * \sqrt{1+1/k},`

which corresponds to Equation 8-1 in Farrington and Andrews (2003).
Note that an aggregation into 4-week blocks occurs in
`algo.cdcLatestTimepoint`

and `m`

denotes number of 4-week
blocks (months) to use as reference values. This function currently
does the same for monthly data (not correct!)

`algo.cdcLatestTimepoint`

returns a list of class `survRes`

(surveillance result), which
includes the alarm value (alarm = 1, no alarm = 0) for recognizing an
outbreak, the threshold value for recognizing the alarm and
the input object of class disProg.

`algo.cdc`

gives a list of class `survRes`

which
includes the vector of alarm values for every timepoint in
`range`

, the vector of threshold values for every timepoint
in `range`

for the system specified by `b`

, `w`

,
the range and the input object of class disProg.

M. Höhle

Stroup, D., G. Williamson, J. Herndon, and J. Karon (1989). Detection
of aberrations in the occurrence of notifiable diseases surveillance data.
*Statistics in Medicine* 8, 323–329.
\Sexpr[results=rd]{tools:::Rd_expr_doi("10.1002/sim.4780080312")}

Farrington, C. and N. Andrews (2003). Monitoring the Health of Populations, Chapter Outbreak Detection: Application to Infectious Disease Surveillance, pp. 203-231. Oxford University Press.

`algo.rkiLatestTimepoint`

,`algo.bayesLatestTimepoint`

and `algo.bayes`

for the Bayes system.

```
# Create a test object
disProgObj <- sim.pointSource(p = 0.99, r = 0.5, length = 500,
A = 1,alpha = 1, beta = 0, phi = 0,
frequency = 1, state = NULL, K = 1.7)
# Test week 200 to 208 for outbreaks with a selfdefined cdc
algo.cdc(disProgObj, control = list(range = 400:500,alpha=0.025))
```

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