# rankorderseg: A function to compute rank-ordered segregation indices In OasisR: Outright Tool for the Analysis of Spatial Inequalities and Segregation

## Description

A function computing Reardon (2011) rank-ordered segregation indices

## Usage

 `1` ```rankorderseg(x, polorder = 4, pred = NULL) ```

## Arguments

 `x` - an object of class matrix (or which can be coerced to that class), where each column represents the distribution of a group within spatial units. The number of columns should be greater than 1 (at least 2 groups are required). You should not include a column with total population, because this will be interpreted as a group. The rows represent the nominal categories (spatial units) and the columns the population distribution as ordered groups divided by thresholds `polorder` - order of the polynomial approximation (4 by default) `pred` - a numerical vector with percentiles to be predicted. If NULL, the predictions are made at threshold levels

## Value

A list containing the results for three rank-ordered indices: rank-order information theory index (Hr), rank-order variation ratio index (Rr) and rank-order square root index (Sr). For each index, a sublist is provided, containing: Index - the rank-ordered index value Hp/Rp/Sp - a vector with ordinal information theory/variance ratio/square root segregation index values at thresholds Coefficients - Coefficients extracted from the polynomial estimation model, including basic statistics Predict - a list contining predicted values of the coresponding ordinal index (fit); standard error of predicted means (se.fit); degrees of freedom for residual (df); and residual standard deviations (residuale.scale). If pred is NULL, the function will return the the statistics at thresholds

## References

Reardon S. F. (2011) Measures of Income Segregation . The Stanford Center on Poverty and Inequality

`ordinalseg`
 ``` 1 2 3 4 5 6 7 8 9 10``` ```x1 <- matrix(nrow = 4, ncol = 7) x1[1,] <- c( 10, 10, 10, 20, 30, 40, 50) x1[2,] <- c( 0, 20, 10, 10, 10, 20, 20) x1[3,] <- c(10, 20, 10, 10, 10, 0, 0 ) x1[4,] <- c(30, 30, 20, 10, 10, 0, 0 ) x2 <- x1 x2[,c(3,4,6,7)] <- x1[,c(6,7,3,4)] rankorderseg(x1) rankorderseg(x2, pred = seq(0, 1, 0.1)) ```