mlef-methods function

Compute maximum likelihood estimates of theta using fence items

mlef is a function for computing maximum likelihood estimates of theta using fence items. methods

mlef(
  object,
  select = NULL,
  resp,
  fence_slope = 5,
  fence_difficulty = c(-5, 5),
  start_theta = NULL,
  max_iter = 100,
  crit = 0.001,
  truncate = FALSE,
  theta_range = c(-4, 4),
  max_change = 1,
  use_step_size = FALSE,
  step_size = 0.5,
  do_Fisher = TRUE
)

## S4 method for signature 'item_pool'
mlef(
  object,
  select = NULL,
  resp,
  fence_slope = 5,
  fence_difficulty = c(-5, 5),
  start_theta = NULL,
  max_iter = 50,
  crit = 0.005,
  truncate = FALSE,
  theta_range = c(-4, 4),
  max_change = 1,
  use_step_size = FALSE,
  step_size = 0.5,
  do_Fisher = TRUE
)

Arguments

• object: an item_pool object.
• select: (optional) if item indices are supplied, only the specified items are used.
• resp: item response on all (or selected) items in the object argument. Can be a vector, a matrix, or a data frame. length(resp) or ncol(resp) must be equal to the number of all (or selected) items.
• fence_slope: the slope parameter to use on fence items. Can be one value, or two values for the lower and the upper fence respectively. (default = 5)
• fence_difficulty: the difficulty parameter to use on fence items. Must have two values for the lower and the upper fence respectively. (default = c(-5, 5))
• start_theta: (optional) initial theta values. If not supplied, EAP estimates using uniform priors are used as initial values. Uniform priors are computed using the theta_range argument below, with increments of .1.
• max_iter: maximum number of iterations. (default = 100)
• crit: convergence criterion to use. (default = 0.001)
• truncate: set TRUE to impose a bound using theta_range on the estimate. (default = FALSE)
• theta_range: a range of theta values to bound the estimate. Only effective when truncate is TRUE. (default = c(-4, 4))
• max_change: upper bound to impose on the absolute change in theta between iterations. Absolute changes exceeding this value will be capped to max_change. (default = 1.0)
• use_step_size: set TRUE to use step_size. (default = FALSE)
• step_size: upper bound to impose on the absolute change in initial theta and estimated theta. Absolute changes exceeding this value will be capped to step_size. (default = 0.5)
• do_Fisher: set TRUE to use Fisher scoring instead of Newton-Raphson method. (default = TRUE)

Returns

mlef returns a list containing estimated values.

• th theta value.
• se standard error.
• conv TRUE if estimation converged.
• trunc TRUE if truncation was applied on th.

Examples

mlef(itempool_fatigue, resp = resp_fatigue_data[10, ])
mlef(itempool_fatigue, select = 1:20, resp = resp_fatigue_data[10, 1:20])

References

Han, K. T. (2016). Maximum likelihood score estimation method with fences for short-length tests and computerized adaptive tests. Applied Psychological Measurement, 40(4), 289-301.