Secondary defenses give you the ability to choose your defense based on what opposing players are on the court. Here is the decision-making process that determines which defense is used:

• If no secondary defense is defined, the primary defense is used.
• If a defensive key player is on the court, the primary defense is used.
• If you have set 1 or 2 defensive key players but none are on the court, the secondary defense is used.
• If one of your specified matchups is in use, the primary defense is used.
• If you have specificed matchups but none are in use, the secondary defense is used.
• Failing all of the above, the primary defense is used.

As you can see, there are two ways of getting a primary/secondary choice made -- key players and matchups. Though there is some overlap, each has slightly different uses. Either way, your secondary defense should always be your general-use defense and your primary defense should be the one geared against the specific players in question.

Opposing Key Players: This is the most common way to employ a secondary defense. You can select 1 or 2 players on the opposing team. If either is on the court you will use the primary defense; if not you use the secondary defense. The usual use is when the other team has 1 or 2 very dangerous players; you would select a primary defense designed to combat them (usually double-player or box-and-1). You need to take great care to ensure that those 1-2 players were the first matchups selected; otherwise a double-player would double-cover somebody else and leave the dangerous players guarded very lightly -- exactly the opposite of what you want! If your opponent has two star players at similar positions, you might opt to go with a different defense. For example, a C-PF tandem might be guarded adequtely well by a 3-2 or double-inside defense, saving you the need to employ the riskier double-man defense.

Matchups: In certain (rare) situations you may feel the need to have more than two "key" opposing players. In that case, you could use the matchups to specify those players (and their defenders); the limitation is that you could not specify matchups on anyone else. One possible use of this would be if you noticed that the other team had three great outside shooters but didn't ensure that one was always on the court. In that case you could specify those three players in matchups, use a normal man or 3-2 zone as your primary defense, and use a double-inside or 2-3 zone as your secondary defense.

• 2-3: strongest inside. The center is under the hoop, with the forwards to his sides, while the guards are on the perimeter. This is the zone equivalent of a double-inside man defense.
• 2-1-2: strongest at medium-range. The center moves towards the free throw line, making the defense stronger against medium-range shots; other players are in their 2-3 assignments. This is the zone equivalent of a double-medium man defense.
• 3-2: strongest on the perimeter. The SF moves to the perimeter, with only the C and PF covering inside. This is the zone equivalent of a double-perimeter man defense.
• matchup zone: balanced defense. The matchup zone is a system that plays very much like man-to-man, except that the defenders more or less stay in their areas of the court. This is accomplished by matching up man-to-man initially and rotating assignments as the offensive players move so that the defenders don't move a whole lot. This is the zone equivalent of a straight man defense.
• box-and-1: guards one player. This defense takes the matchup in the matchup list as a man assignment, with the remaining four players playing a loose zone. This is the zone equivalent of a double-player man defense.

The main advantage of zone is its ease of use. You can "hide" a bad defender without having to define all possible matchup combinations. However, man coverage gives you much more control, most notably the chance to double a specific player to shut him down and the chance to put a poor defender guarding a weak shooter.

To help coaches understand how settings will affect a team, several "prototype scrimmage" runs have been made. Note that the actual percentages will vary based on personnel, opponent, etc.; what is more significant here is the variation of statistics as coaching options are modified.

The data columns show the following values:

• Percentage of possessions resulting in inside shot attempts, percentage of inside shot attempts made, and quality of coverage on the inside area (1.0 = straight man with no help).
• Percentage of possessions resulting in inside shot attempts, percentage of inside shot attempts made, and quality of coverage on the inside area (1.0 = straight man with no help).
• Percentage of possessions resulting in inside shot attempts, percentage of inside shot attempts made, and quality of coverage on the inside area (1.0 = straight man with no help).
• Percentage of possessions resulting in inside shot attempts, percentage of inside shot attempts made, and quality of coverage on the inside area (1.0 = straight man with no help).
• Percentage of possessions resulting in a fast break opportunity
• Percentage of possessions resulting in a shooting foul (not counting a free throw following a successful field goal)
• Percentage of possessions resulting in a turnover or offensive foul that is not scored a steal
• Percentage of possessions resulting in a steal
• Percentage of field goals with an assist scored
• Percentage of field goal attempts made after a drive

• The stats shown below are not "perfect", in the sense of noiseless. They are taken from real prototype scrimmages, and thus are affected by random draws. To get a sense of the size of this effect, one can compare the "nominal" lines from each block below, which in theory should all be identical. That is, differences between the 3-pass line, moderate motion, straight shooting, moderate press, moderate trap, and straight man defense lines are due entirely to the random draws.
• Inside, 10-footer, and 15-footer zones are defined identically to the box score breakdown
• A possession is defined as the number of times a team takes possession of the ball plus the number of offensive rebounds. (In other words, a possession that ends in a missed shot and offensive rebound counts as two possessions.
• All settings other than the one being tested are set as follows: 3 pass, moderate motion, moderate press, moderate trap, straight shooting, and straight man defense. The opposing team also has these settings.
• For offensive options, the team's own stats are shown. For defensive options, the opponent's stats are shown.

Offense Options

 inside   10-footer 15-footer 3-pointer FB FT TO St As Dr
%a %m cov %a %m cov %a %m cov %a %m cov %a %a %a %a %m %a
18 40 1.4 23 38 1.0 13 34 1.0 18 27 0.9  5  9  7  6 68 15 1-pass
17 42 1.5 22 41 1.1 10 32 1.0 24 26 0.9  5  9  6  8 67  7 2-pass
17 46 1.5 21 40 1.1  6 38 1.0 24 29 1.0  5  9  7  9 66  4 3-pass
17 43 1.5 18 44 1.1  7 28 1.0 22 32 1.0  6  7 10 12 60  4 4-pass
14 50 1.5 17 45 1.1  6 29 1.0 20 27 1.0  6  9 12 17 60  3 5-pass

 inside   10-footer 15-footer 3-pointer FB FT TO St As Dr
%a %m cov %a %m cov %a %m cov %a %m cov %a %a %a %a %m %a
18 44 1.5 20 39 1.1  7 36 1.0 23 30 1.0  4  8  8 10 65  9 least motion
18 47 1.5 20 41 1.1  9 42 1.0 22 28 0.9  5  9  8  8 65  5 less motion
18 46 1.5 21 42 1.1  8 33 1.0 26 33 1.0  4  8  7  9 68  2 normal motion
17 49 1.5 20 47 1.1  9 35 1.0 24 27 1.0  5  9  7  9 68  2 more motion
16 51 1.5 21 41 1.1  8 29 1.0 26 32 1.0  4  9  8  9 68  1 most motion

 inside   10-footer 15-footer 3-pointer FB FT TO St As Dr
%a %m cov %a %m cov %a %m cov %a %m cov %a %a %a %a %m %a
17 46 1.5 21 44 1.1  7 43 1.0 24 29 1.0  5  8  8 10 68  3 straight
28 39 1.5 22 44 1.1  2 46 1.0 11 27 0.9  5 11 11  9 55  8 moderate inside
16 47 1.5 33 38 1.1 12 40 1.0  6 35 1.0  6 10  7 11 66  7 moderate medium
 5 50 1.5 21 40 1.1 16 32 1.0 32 24 1.0  4  7  7  8 68  3 moderate perimeter

• The pass setting provides a fairly significant tradeoff between moving the ball around to create the best shot, versus the non-zero turnover probability associated with each pass. For the set of prototype players used here, the optimum value appears to have been 3-pass, but this will vary strongly with your players' passing, scoring, and intelligence skills. Note also that a 5-pass setting can result in forced shots as the shot clock gets low.
• The motion setting is genrally a tradeoff between letting players make their own shots (via their scoring skill) and using picks. As such, its effectiveness is highly dependent on your personnel, and one doesn't see a whole lot of variation in stats caused by the motion settings, aside from the percentage of shots taken off a drive.
• Shooting location is purely an attempt to shoot the ball from preferred locations on the court. Since the simulation already accounts for shot probabilities (including both your players' and your opponents' skills), overuse of this setting is likely to cause your team to force bad shots. However, it can be useful as a minor adjustment to your team's shooting distribution.

Defense Options

 inside   10-footer 15-footer 3-pointer FB FT TO St As Dr
%a %m cov %a %m cov %a %m cov %a %m cov %a %a %a %a %m %a
19 46 1.5 21 45 1.1  9 30 1.0 24 29 1.0  3  8  8  8 67  2 least press
18 47 1.5 22 37 1.1  8 36 1.0 25 29 1.0  4  7  7  9 71  3 less press
18 50 1.5 20 42 1.1  7 34 1.0 25 29 1.0  4  8  7  9 66  3 normal press
18 43 1.5 19 38 1.1  9 30 1.0 22 30 1.0  6  8  8  9 63  3 more press
16 42 1.5 19 40 1.1  8 34 1.0 23 31 1.0  7  8  8 10 66  3 most press

 inside   10-footer 15-footer 3-pointer FB FT TO St As Dr
%a %m cov %a %m cov %a %m cov %a %m cov %a %a %a %a %m %a
17 46 1.3 22 42 0.7  8 32 0.7 26 28 0.7  4  7  7  7 35  4 least trap
17 40 1.5 22 40 1.0  8 39 1.0 24 30 0.9  5  8  9  8 58  4 less trap
17 50 1.5 20 44 1.1  8 38 1.0 23 31 0.9  6  8  9  9 68  3 normal trap
16 43 1.5 18 47 1.1  8 40 1.0 25 30 0.9  5  8  9  9 81  3 more trap
15 45 1.4 19 44 1.1  9 40 1.1 26 36 0.9  6  6  9 11 87  2 most trap

 inside   10-footer 15-footer 3-pointer FB FT TO St As Dr
%a %m cov %a %m cov %a %m cov %a %m cov %a %a %a %a %m %a
16 44 1.5 19 45 1.1  8 34 1.0 25 34 1.0  6  9  8 10 68  2 straight man
16 41 1.5 21 45 1.1  8 36 0.9 26 32 0.9  5  9  7  8 58  3 double inside 60%
24 46 1.1 11 41 1.3  9 39 0.9 28 33 0.8  6  8  7  8 58  3 double medium 60%
25 52 1.1 19 41 1.0  6 38 1.2 17 30 1.2  6  9  8 10 77  2 double perimeter 60%
20 45 1.3 18 44 1.1  6 40 1.0 27 30 0.9  4  7  7  9 66  3 double C 60%
20 46 1.3 17 42 1.1  8 40 1.1 26 31 0.9  5  8  8 10 68  2 double PF 60%
21 52 1.3 17 42 1.1  6 40 1.0 24 32 1.0  5  9  8 10 63  3 double SF 60%
21 50 1.3 19 45 1.0  6 41 1.1 24 31 1.0  4  9  8  9 67  3 double SG 60%
21 49 1.3 20 45 1.1  9 34 1.0 21 32 1.0  5  8  7  9 72  2 double PG 60%
15 44 1.5 22 44 1.0  9 33 0.8 26 32 0.8  5  8  6  7 48  4 2-3 zone
22 50 1.2 11 36 1.3  9 32 0.8 27 30 0.8  5  9  7  9 49  2 2-1-2 zone
28 50 0.8 22 43 0.9  4 39 1.3 13 27 1.3  6 11  8  9 83  4 3-2 zone
18 44 1.4 18 44 1.1  8 41 1.0 26 33 0.9  5  7  8 10 62  2 matchup zone
21 52 1.1 16 42 1.1  6 34 0.9 26 33 0.8  5  8  8  9 57  4 box+C
23 48 1.1 15 45 1.1  7 41 1.1 27 29 0.8  5  7  7  9 60  4 box+PF
24 49 1.0 15 39 1.0  5 34 1.0 24 31 1.0  6  8  8 10 62  1 box+SF
25 48 1.0 18 41 1.0  5 33 1.1 22 31 1.0  5  8  8  9 59  3 box+SG
25 50 1.0 18 42 1.0  9 39 0.9 18 36 1.1  5  8  8  9 80  2 box+PG

• Because the press is active before the opponent enters a halfcourt set, the primary effect one will see with heavy pressing is a higher number of opponent fast breaks (when they break the press) as well as a higher number of turnovers and steals (the latter of which frequently lead to your fast breaks). Opponent shot selection and percentages if they get into a halfcourt set are largely unchanged. Heavy pressing can be a good tradeoff if your opponent has poor ball handling guards, but is more often used as an attempt to force steals if trailing late.
• The trap is an attempt to double-cover the player with the ball. If the opponent has good ball handlers, they can often pass out of trouble; thus the higher number of assists and generally higher shooting percentage with trapping. However, it will create more turnovers as well.
• The primary effect of defense type is to attempt to prevent the opponent from scoring in a particular part of the floor or by a particular player, at the expense of making it easier to score elsewhere or by other players. If your defense has a weakness, or your opponent has a particularly dangerouls player, this is often a good tradeoff.

This visualization tool shows rough defensive positions (for each defense), passing depths, and shooting depths.