# Overview

Throughout Marketscape you will find some counts and performance metrics that do not include actual numbers. This article explains the alternative entries.

## <11

Our data is derived from the CMS Virtual Research Data Center. In order to maintain the levels of patient confidentiality required by CMS, all counts and percentages that could reveal a patient count less than 11 will be indicated by <11 in that cell in the table.

- For
**counts**, <11 is used for any patient count less than eleven (11). - For
**percentages**, this would represent any instances where the calculation includes a patient count that is less that eleven (11) in the denominator. In these cases, the percentage is replaced with "ins." See below.

## ins

"ins" stands for insignificant or insufficient. You can think of this two ways: we have insufficient data to make a meaningful calculation, *or* when calculated, the result turned out to be insignificant.

Sometimes when we calculate a performance statistic, the final number is too small, or too small statistically to be meaningful. Also, the size of the data pool used in calculating some numbers is too small to provide a meaningful final number. In all of these cases, we present the response "ins" to indicate that, after calculation, the data has no value. See **Statistical Significance for Solution Display**.

Hyphen, “-“

A hyphen is a null - it means that no metric was calculated for the cell.

## Zero (0)

Zero is used when a metric is calculated and the count is zero or the percent is zero %.

It is important to distinguish between "-" and 0. If a table cell contains "-" this means that we did not calculate the metric. A zero is the result of a calculation that returned a result of zero or zero percent - 0%.

## Statistical Significance for Solution Display

Calculated fields exist in Mosaic for which the denominator of the patient population is sometimes known, and sometimes unknown. Per CMS rules, no field can be displayed if the cell value is 10 or less. However, when calculating certain measures, Trella Health increases the limits on the patient denominator to ensure statistical significance. If the statistical significance threshold is not met, a value of “ins” is displayed to denote “insignificant” patient population.

### Examples:

**Average Length of Stay (ALOS)**

Since ALOS is a metric calculated for a patient population that is solely within the confines of the agency to control, Trella Health displays this measure when the population of patients is >10 patients. Thus, if the number of patients is not <11, the ALOS will be displayed. Otherwise, “ins” is displayed.

**Performance Metrics**

Performance metrics are measures that typically involved another provider (e.g., hospitalizations and readmit rates). To ensure anomalies in the data are smoothed and a significant patient population is available, Trella creates these measures using a two-year population of patients. In this case, the threshold is 30 patients, otherwise “Ins” is displayed. This enables 30 patients for a denominator when creating two-year rates, and for one-year (rare) the threshold would be 15 patients. By calculating these rates in this way, we can display low rates by mandating a large denominator for the patient population, and calculating the measure over two years, ensuring the calculation cannot be applied to a patient count of one year.