Power Score
Power Score is derived from the new calibration movies, now known as "Power Movies." Each Power Movie has been assigned a value between 2 and 75 points by the Stardust@home science team. Some Power Movies will be nearly impossible to spot (on purpose). Also, if you miss a Power Movie, your score will not lower.

Skill Score
Skill is a measure of how often you are able to identify a track when one is presented to you. The score is your Power Score divided by the number of Power Movies you've searched so far. You have to search at least 50 Power Movies before your score is calculated.

New for Phase IV! Certificates
Certificates will be awarded for finding tracks. We have retired the Milestone Certificates along with the previous scoring system. In Phase IV we will recognize any Duster who clicks on a movie containing a track, not just the first. The timeline will go like this: periodically promising movies are promoted for review by a Red Team member or by virtue of the number of positive clicks. If we review the movie and think there is a track, we promote it to the Candidates page. At that point, everyone who clicked on a movie containing that track gets a certificate. The first Duster who clicked gets the naming rights.

Incidentally, as we find new tracks we will make new Power Movies from them. Once that happens, we will not award a certificate for clicking on a candidate track movie.)

Calibration Movie
A focus movie for which we know the answer. We created the calibration movies using Stardust aerogel movies, but some of them have tracks digitally inserted. We used images of tracks from laboratory shots into Earth-bound test aerogel. When you use the Virtual Microscope, some of the focus movies you see will be calibration movies. They may or may not have a track in them, but they are all in focus. We use them to test your skill at recognizing tracks.

Focus Movie
A stack of images taken from a single field of view of the automated microscope at several different focus depths. Each image can be thought of as a frame in a movie; running the movie forward and backward by sliding your mouse up and down the focus bar in the Virtual Microscope is equivalent to looking throgh a real microsope and turning the focus knob.

FOV
A field of view, particularly in a microscope. Pronounced "fove".

List of Data Viewed
Listing of track candidates that you have identified.

Number of Agreements
In the My Events page: the number of people who agreed with you that a certain movie really does contain a track. This number includes yourself!

Rank
Your rank is determined by comparing your score to the scores of other volunteers. If your rank is 150, that means there are 149 volunteers who have a higher score than you do. Your rank is recalculated every few minutes.

Real Movie
An ordinary focus movie, created from the aerogel that flew on the Stardust mission. (As opposed to a Calibration Movie.)

Score (Phases I, II and III)
Your score is the total number of calibration movies you have identified correctly minus the number of calibration movies you have answered incorrectly. Most movies are not calibration movies, and will not affect your score. Score was replaced with Power Score in Phase IV.

Sensitivity (Phases I, II and III)
Sensitivity measures how well you are able to correctly identify calibration tracks. Sensitivity is the total number of tracks you have correctly identified in calibration movies divided by the total number of calibration movies you have searched in which there were actually tracks.

Specificity (Phases I, II and III)
Specificity measures how well you are able to correctly identify a calibration movie that contains no track. Specificity is the total number of times you have correctly found no track in calibration movies divided by the total number of calibration movies you have searched in which there were actually no tracks.

VM
Virtual Microscope, the program used by Stardust@home allowing volunteers to view focus movies from the Stardust Interstellar Dust Collector.

WCO
On the MyEvents page, in the comments column, short-hand for "Worth Checking Out".