Nearly a quarter into the NBA season, the Rockets stand at 9-11, two games behind 0.500. As a team, Houston ranks 10th in offensive efficiency, scoring a robust 103 points per 100 possessions but ranks sixth worst in defensive efficiency, giving up nearly 104 points per 100 possessions. As these two stats imply, Houston has a negative scoring margin this season of almost one point per game. Extrapolated over a season, this translates to a 39-win team per the Pythagorean wins formula. A 39-43 record is almost certainly not good enough to make the playoffs in a Western conference that, outside of the 5 playoff locks (both LA teams, Memphis, San Antonio, and OKC), boasts a bevy of mid-tier playoff hopefuls in Denver, Minnesota, Utah, Golden State, and Dallas.To become a more competitive team, the Rockets need improve defensively. On the surface, the Rockets defensive struggles are not altogether surprising. Houston has the youngest team in the league, a relatively inexperienced coach, and a roster full of players in their first season in a Rockets’ uniform. Such a team can hardly be expected to defend on a string as the Bulls and Celtics do. Those squads are equipped with proven defensive philosophies that have stood the test of over a half decade of NBA games. Moreover, outside of Asik, Chandler and Toney Douglas, the Rockets really don’t have any players that are much better than average defensively.Looking at the available team defensive data, a few issues stand out. The Rockets are allowing opponents to take and make a higher percentage of three point shots than the league average. According to Hoopdata, Houston allows the 9th highest three-point rate, with 25% of opponent field goal attempts coming from beyond the arc. The Rockets are allowing opponents to shoot 39% from deep, the 4th highest rate in the league and well above the league average of 36%. In spot-up situations, which comprise 19% of opponent possessions, Houston is allowing 1.01 points per possession (22nd in the league) as well as 40% shooting from three (Synergy Sports). This relatively poor three-point defense, coupled with the fact that opponents are shooting 66% at the rim (vs. the league average of 64%) means that Houston is giving up the 6th highest true shooting percentage (55%) amongst NBA teams.The other area in which Houston struggles is transition defense. According to Synergy Sports, 14% of opponent possessions come via the fast break, and Houston gives up 1.22 points per possession in these scenarios, 5th worst in the league. For a team that leads the NBA in pace by a mile, (per Hollinger, Houston uses 99 possessions per game) it is unsurprising that opponents are able to generate fast-break opportunities following Rockets’ misses and turnovers. To some extent, this may be the price to pay for playing at such a fast pace (and with such a young team), until and unless McHale urges his players to prioritize transition defense as teams like the Celtics do. Per Hoopdata, Boston ranks dead last in offensive rebound rate, a result of their focus on getting back on defense after missed shots.One very positive aspect, however, is Houston’s foul rate and free throw defense. Young and relatively undisciplined teams often compensate for a lack of defensive cohesion by fouling at high rates and sending opponents to the line for high efficiency free throws. The Rockets, despite having the youngest roster in the NBA, foul at a league-average rate. Indeed, according to Team Rankings, just under 15% of opponent points come from free throws, the lowest percentage in the league. The ability to defend without fouling is more often embraced by experienced teams like the Spurs, and it’s encouraging to see the Rockets using this defensive philosophy.The fact remains that the Rockets are a below-average defensive team, one whose starting line-up gives up 9 more points per 100 possessions than it scores (82games.com). Nonetheless, a young team can be expected to struggle on defense, which in the NBA relies more on communication, a consistent scheme of rotations, and a willingness to cover for others’ mistakes than on individual skill and athleticism (unless you’re blessed with a Dwight Howard or a perimeter stopper à la Tony Allen or Thabo Sefalosha). The Rockets have the ingredients in terms of personnel to become a better defensive team: it will be up to McHale and staff to figure out the best use of the Rockets youth and athleticism.