The health of a project is based on two indices: SPI and CPI (See SPI and CPI thresholds to learn more).

CPI Calculation

CPI is calculated as follows:

1) If Hours left = 0, the following formula is used:

2) If Hours left > 0, the following formula is used:

SPI Calculation

SPI is calculated using the formula:

where:

• StartDate, EndDate, Progress, HoursLeft, and ActualHours are project parameters,
• EstimatedHours is a total of estimated hours of all the project's activities plus the project's own estimated hours, and
• CurrentDate is the current date.

A project whose start date is Today has an SPI value as set in the Account Settings even if it has zero progress.

"Definitely bad" index

SPI is 'definitely bad' when the project's end date is in the past.

CPI is 'definitely bad' when Actual Hours > Estimated Hours and Hours left = 0.

Health color coding

The chart explains the color coding being used to show what health a given activity/project has:

CPI/SPI Values	Color Code	Comments
Both indices are at or above their thresholds.		Healthy project (when one of the indices is good and the other is unavailable*, or both SPI and CPI are good)
One index is below and the other is above its threshold or N/A.		Activity/Project at moderate risk (CPI is good and SPI is bad, or vice versa)
Both indices are below their thresholds.		Project is at high risk (both CPI and SPI are below the threshold, or either SPI or CPI is definitely bad (DB))
* The conditions under which SPI and CPI are not calculated (not available) are given in the notes below.

CPI/SPI Threshold

The default threshold for both CPI and SPI is 1.

The threshold is a value you set to match CPI and SPI against.

Generally, the higher the threshold the stricter your requirement for cost or schedule performance will be.

However, setting the thresholds needs to be done with care. For example, 'having a CPI that is very high (in some cases, very high is only 1.2) may mean that the plan was too conservative, and thus a very high number may in fact not be good, as the CPI is being measured against a poor baseline. Management or the customer may be upset with the planners as an overly conservative baseline ties up available funds for other purposes, and the baseline is also used for manpower planning.' (a Wikipedia article on EVA).

Calculating CPI and SPI individually

Use 'Allow calculating CPI and SPI individually' (Settings > General > Advanced settings > Project Health (Earned Value Analysis) settings) to make sure one of the indices is calculated when the other one is unavailable.

If a project has zero actual hours, CPI is not calculated at all. Such a project will be 'green' if its SPI is above the threshold. If SPI is below the threshold, the project is 'yellow' (at risk) if it is on schedule, or 'red' (troubled) otherwise.

Only projects with the following characteristics are used in the calculation:

1. Project's start date is preceding the current date so the project is ongoing, and
2. Project's status is treat-as-open or treat-as-hold – those with a status treat-as-complete, e.g. Closed, Completed, etc. (see Workflow for details), are not included in the calculation.