check_interval {suddengains}

Check if a given interval is a sudden gain/loss

Description

Checks if a specific session to session interval is a sudden gain/loss.

Usage

check_interval(
  pre_values,
  post_values,
  sg_crit1_cutoff,
  sg_crit2_pct = 0.25,
  sg_crit3 = TRUE,
  sg_crit3_alpha = 0.05,
  sg_crit3_adjust = TRUE,
  sg_crit3_critical_value = 2.776,
  identify = c("sg", "sl"),
  details = TRUE
)

Arguments

pre_values

Vector, three pre gain/loss values to be checked for a sudden gain/loss (n-2, n-1, n)

post_values

Vector, three post gain/loss values to be checked for a sudden gain/loss (n+1, n+2, n+3)

sg_crit1_cutoff

Numeric, specifying the cut-off value to be used for the first sudden gains criterion. The function define_crit1_cutoff can be used to calculate a cutoff value based on the Reliable Change Index (RCI; Jacobson & Truax, 1991). If set to NULL the first criterion wont be applied.

sg_crit2_pct

Numeric, specifying the percentage change to be used for the second sudden gains/losses criterion. If set to NULL the second criterion wont be applied.

sg_crit3

If set to TRUE the third criterion will be applied automatically adjusting the critical value for missingness. If set to FALSE the third criterion wont be applied.

sg_crit3_alpha

Numeric, alpha for the student t-test (two-tailed) to determine the critical value to be used for the third criterion. Degrees of freedom are based on the number of available data in the three sessions preceding the gain and the three sessions following the gain.

sg_crit3_adjust

Logical, specify whether critical value gets adjusted for missingness, see Lutz et al. (2013) and the documentation of this R package for further details. This argument is set to TRUE by default adjusting the critical value for missingness as described in the package documentation and Lutz et al. (2013): A critical value of 2.776 is used when all three data points before and after a potential gain are available, where one data point is missing either before or after a potential gain a critical value of 3.182 is used, and where one data point is missing both before and after the gain a critical value of 4.303 is used. If set to FALSE a critical value of 2.776 will instead be used for all comparisons, regardless of missingnes in the sequence of data points that are investigated for sudden gains.

sg_crit3_critical_value

Numeric, specifying the critical value to instead be used for all comparisons, regardless of missingnes in the sequence of data points that are investigated for potential sudden gains.

identify

String, specifying whether to identify sudden gains ("sg") or sudden losses ("sl").

details

Logical, details yes no?

Value

Information on whether a given interval is a sudden gain/loss

Examples

# Check interval for sudden gain using all 3 criteria
# No missing data, alpha = 0.05
check_interval(pre_values = c(32, 31, 33),
               post_values = c(5, 6, 7),
               sg_crit1_cutoff = 7,
               sg_crit2_pct = .25,
               sg_crit3 = TRUE,
               sg_crit3_alpha = .05,
               identify = "sg")

# No missing data, alpha = 0.01
check_interval(pre_values = c(32, 31, 33),
               post_values = c(5, 6, 7),
               sg_crit1_cutoff = 7,
               sg_crit2_pct = .25,
               sg_crit3 = TRUE,
               sg_crit3_alpha = .01,
               identify = "sg")

# Check interval for sudden gain using only third criterion
# Some missing data, alpha = 0.01
check_interval(pre_values = c(NA,31,33),
               post_values = c(5, NA, 7),
               sg_crit1_cutoff = NULL,
               sg_crit2_pct = NULL,
               sg_crit3 = TRUE,
               sg_crit3_alpha = .01,
               identify = "sg")

# Check interval for sudden loss using all three criteria
# Some missing data, alpha = 0.05
check_interval(pre_values = c(5, NA, 7),
               post_values = c(16, 12, 14),
               sg_crit1_cutoff = -7,
               sg_crit2_pct = .25,
               sg_crit3 = TRUE,
               sg_crit3_alpha = .05,
               identify = "sl")