problink_em function

Calculate EM-estimates of m- and u-probabilities

problink_em(
  formula,
  data,
  patterns,
  mprobs0 = list(0.95),
  uprobs0 = list(0.02),
  p0 = 0.05,
  tol = 1e-05,
  mprob_max = 0.999,
  uprob_min = 1e-04
)

Arguments

• formula: a formula object with the variables for which to calculate the m- and u-probabilities. Should be of the form ~ var1 + var2.

• data: data set with pairs on which to estimate the model. Alternatively one can use the patterns argument.

• patterns: table of patterns (as output by tabulate_patterns).

• mprobs0, uprobs0: initial values of the m- and u-probabilities. These should be lists with numeric values. The names of the elements in the list should correspond to the names in by_x in compare_pairs.

• p0: the initial estimate of the probability that a pair is a match.

• tol: when the change in the m and u-probabilities is smaller than tol

  the algorithm is stopped.

• mprob_max: maximum values of the estimated m-probabilities. Values equal to one can lead to numerical instabilities.

• uprob_min: maximum values of the estimated m-probabilities. Values equal to zero can lead to numerical instabilities.

Returns

Returns an object of type problink_em. This is a list containing the estimated mprobs, uprobs and overall linkage probability p. It also contains the table of comparison patterns.

Examples

data("linkexample1", "linkexample2")
pairs <- pair_blocking(linkexample1, linkexample2, "postcode")
pairs <- compare_pairs(pairs, c("lastname", "firstname", "address", "sex"))
model <- problink_em(~ lastname + firstname + address + sex, data = pairs)
summary(model)

References

Fellegi, I. and A. Sunter (1969). "A Theory for Record Linkage", Journal of the American Statistical Association. 64 (328): pp. 1183-1210. tools:::Rd_expr_doi("doi:10.2307/2286061") .

Herzog, T.N., F.J. Scheuren and W.E. Winkler (2007). Data Quality and Record Linkage Techniques, Springer.