# Rank Cases: Types

You can select multiple ranking methods. A separate ranking variable is created for each method. Ranking methods include simple ranks, Savage scores, fractional ranks, and percentiles. You can also create rankings based on proportion estimates and normal scores.

Rank. Simple rank. The value of the new variable equals its rank.

Savage score. The new variable contains Savage scores based on an exponential distribution.

Fractional rank. The value of the new variable equals rank divided by the sum of the weights of the nonmissing cases.

Fractional rank as percent. Each rank is divided by the number of cases with valid values and multiplied by 100.

Sum of case weights. The value of the new variable equals the sum of case weights. The new variable is a constant for all cases in the same group.

Ntiles. Ranks are based on percentile groups, with each group containing approximately the same number of cases. For example, 4 Ntiles would assign a rank of 1 to cases below the 25th percentile, 2 to cases between the 25th and 50th percentile, 3 to cases between the 50th and 75th percentile, and 4 to cases above the 75th percentile.

Proportion estimates. Estimates of the cumulative proportion of the distribution corresponding to a particular rank.

Normal scores. The z scores corresponding to the estimated cumulative proportion.

**Proportion Estimation
Formula.** For proportion estimates and normal scores, you
can select the proportion estimation formula: Blom, Tukey, Rankit, or Van
der Waerden.

- Blom. Creates new ranking variable based on proportion estimates that uses the formula (r-3/8) / (w+1/4), where w is the sum of the case weights and r is the rank.
- Tukey. Uses the formula (r-1/3) / (w+1/3), where r is the rank and w is the sum of the case weights.
- Rankit. Uses the formula (r-1/2) / w, where w is the number of observations and r is the rank, ranging from 1 to w.
- Van der Waerden. Van der Waerden's transformation, defined by the formula r/(w+1), where w is the sum of the case weights and r is the rank, ranging from 1 to w.

Selecting Ranking Methods

- From the menus choose:
- Select one or more variables to rank. You can rank only numeric variables.
- Click Rank Types.
- Select one
or more ranking methods. A separate variable is created for each ranking
method.
To create ranks based on proportion estimates or normal scores:

- Select Proportion estimates and/or Normal scores.
- Select a ranking method.