Sports Reference Blog

Historical Western Conference vs Eastern Conference Disparity

Posted by Neil on December 5, 2013

In light of the Eastern Conference's "embarrassing" showing in games against the West so far this year, here's a rundown of how each conference has fared against the other for every year since 1951 (before 1971, the NBA had Eastern and Western "divisions" which were de facto conferences):

+---------+--------+--------+-----------+--------+--------+-----------+--------+--------+-------+-------+
| year_id | east_w | east_l | east_wpct | west_w | west_l | west_wpct | e_vs_w | w_vs_e | e_h2h | w_h2h |
+---------+--------+--------+-----------+--------+--------+-----------+--------+--------+-------+-------+
|    2014 |    118 |    155 | 43.2%     |    157 |    120 | 56.7%     |     26 |     63 | 29.2% | 70.8% |
|    2013 |    577 |    651 | 47.0%     |    652 |    578 | 53.0%     |    188 |    262 | 41.8% | 58.2% |
|    2012 |    474 |    516 | 47.9%     |    516 |    474 | 52.1%     |    114 |    156 | 42.2% | 57.8% |
|    2011 |    579 |    651 | 47.1%     |    651 |    579 | 52.9%     |    189 |    261 | 42.0% | 58.0% |
|    2010 |    594 |    636 | 48.3%     |    636 |    594 | 51.7%     |    204 |    246 | 45.3% | 54.7% |
|    2009 |    621 |    609 | 50.5%     |    609 |    621 | 49.5%     |    231 |    219 | 51.3% | 48.7% |
|    2008 |    582 |    648 | 47.3%     |    648 |    582 | 52.7%     |    192 |    258 | 42.7% | 57.3% |
|    2007 |    583 |    647 | 47.4%     |    647 |    583 | 52.6%     |    193 |    257 | 42.9% | 57.1% |
|    2006 |    588 |    642 | 47.8%     |    642 |    588 | 52.2%     |    198 |    252 | 44.0% | 56.0% |
|    2005 |    584 |    646 | 47.5%     |    646 |    584 | 52.5%     |    194 |    256 | 43.1% | 56.9% |
|    2004 |    559 |    671 | 45.4%     |    630 |    518 | 54.9%     |    154 |    266 | 36.7% | 63.3% |
|    2003 |    575 |    655 | 46.7%     |    614 |    534 | 53.5%     |    170 |    250 | 40.5% | 59.5% |
|    2002 |    593 |    637 | 48.2%     |    596 |    552 | 51.9%     |    188 |    232 | 44.8% | 55.2% |
|    2001 |    566 |    664 | 46.0%     |    623 |    525 | 54.3%     |    161 |    259 | 38.3% | 61.7% |
|    2000 |    598 |    632 | 48.6%     |    591 |    557 | 51.5%     |    193 |    227 | 46.0% | 54.0% |
|    1999 |    379 |    371 | 50.5%     |    346 |    354 | 49.4%     |     46 |     38 | 54.8% | 45.2% |
|    1998 |    648 |    582 | 52.7%     |    541 |    607 | 47.1%     |    243 |    177 | 57.9% | 42.1% |
|    1997 |    647 |    583 | 52.6%     |    542 |    606 | 47.2%     |    242 |    178 | 57.6% | 42.4% |
|    1996 |    619 |    611 | 50.3%     |    570 |    578 | 49.7%     |    214 |    206 | 51.0% | 49.0% |
|    1995 |    550 |    598 | 47.9%     |    557 |    509 | 52.3%     |    158 |    206 | 43.4% | 56.6% |
+---------+--------+--------+-----------+--------+--------+-----------+--------+--------+-------+-------+
| year_id | east_w | east_l | east_wpct | west_w | west_l | west_wpct | e_vs_w | w_vs_e | e_h2h | w_h2h |
+---------+--------+--------+-----------+--------+--------+-----------+--------+--------+-------+-------+
|    1994 |    562 |    586 | 49.0%     |    545 |    521 | 51.1%     |    170 |    194 | 46.7% | 53.3% |
|    1993 |    583 |    565 | 50.8%     |    524 |    542 | 49.2%     |    191 |    173 | 52.5% | 47.5% |
|    1992 |    573 |    575 | 49.9%     |    534 |    532 | 50.1%     |    181 |    183 | 49.7% | 50.3% |
|    1991 |    521 |    545 | 48.9%     |    586 |    562 | 51.0%     |    170 |    194 | 46.7% | 53.3% |
|    1990 |    517 |    549 | 48.5%     |    590 |    558 | 51.4%     |    166 |    198 | 45.6% | 54.4% |
|    1989 |    522 |    462 | 53.0%     |    503 |    563 | 47.2%     |    186 |    126 | 59.6% | 40.4% |
|    1988 |    464 |    438 | 51.4%     |    479 |    505 | 48.7%     |    145 |    119 | 54.9% | 45.1% |
|    1987 |    465 |    437 | 51.6%     |    478 |    506 | 48.6%     |    146 |    118 | 55.3% | 44.7% |
|    1986 |    460 |    442 | 51.0%     |    483 |    501 | 49.1%     |    141 |    123 | 53.4% | 46.6% |
|    1985 |    462 |    440 | 51.2%     |    481 |    503 | 48.9%     |    143 |    121 | 54.2% | 45.8% |
|    1984 |    461 |    441 | 51.1%     |    482 |    502 | 49.0%     |    142 |    122 | 53.8% | 46.2% |
|    1983 |    458 |    444 | 50.8%     |    485 |    499 | 49.3%     |    139 |    125 | 52.7% | 47.3% |
|    1982 |    461 |    441 | 51.1%     |    482 |    502 | 49.0%     |    142 |    122 | 53.8% | 46.2% |
|    1981 |    466 |    436 | 51.7%     |    477 |    507 | 48.5%     |    147 |    117 | 55.7% | 44.3% |
|    1980 |    454 |    448 | 50.3%     |    448 |    454 | 49.7%     |    124 |    118 | 51.2% | 48.8% |
|    1979 |    425 |    477 | 47.1%     |    477 |    425 | 52.9%     |    205 |    257 | 44.4% | 55.6% |
|    1978 |    428 |    474 | 47.5%     |    474 |    428 | 52.5%     |    208 |    254 | 45.0% | 55.0% |
|    1977 |    436 |    466 | 48.3%     |    466 |    436 | 51.7%     |    216 |    246 | 46.8% | 53.2% |
|    1976 |    388 |    350 | 52.6%     |    350 |    388 | 47.4%     |    181 |    143 | 55.9% | 44.1% |
|    1975 |    378 |    360 | 51.2%     |    360 |    378 | 48.8%     |    171 |    153 | 52.8% | 47.2% |
+---------+--------+--------+-----------+--------+--------+-----------+--------+--------+-------+-------+
| year_id | east_w | east_l | east_wpct | west_w | west_l | west_wpct | e_vs_w | w_vs_e | e_h2h | w_h2h |
+---------+--------+--------+-----------+--------+--------+-----------+--------+--------+-------+-------+
|    1974 |    315 |    341 | 48.0%     |    382 |    356 | 51.8%     |    131 |    157 | 45.5% | 54.5% |
|    1973 |    318 |    338 | 48.5%     |    379 |    359 | 51.4%     |    134 |    154 | 46.5% | 53.5% |
|    1972 |    283 |    373 | 43.1%     |    414 |    324 | 56.1%     |    125 |    215 | 36.8% | 63.2% |
|    1971 |    291 |    365 | 44.4%     |    406 |    332 | 55.0%     |    139 |    213 | 39.5% | 60.5% |
|    1970 |    309 |    265 | 53.8%     |    265 |    309 | 46.2%     |    169 |    125 | 57.5% | 42.5% |
|    1969 |    314 |    260 | 54.7%     |    260 |    314 | 45.3%     |    176 |    122 | 59.1% | 40.9% |
|    1968 |    274 |    218 | 55.7%     |    218 |    274 | 44.3%     |    154 |     98 | 61.1% | 38.9% |
|    1967 |    223 |    182 | 55.1%     |    182 |    223 | 44.9%     |    133 |     92 | 59.1% | 40.9% |
|    1966 |    184 |    136 | 57.5%     |    176 |    224 | 44.0%     |    124 |     76 | 62.0% | 38.0% |
|    1965 |    181 |    139 | 56.6%     |    179 |    221 | 44.8%     |    121 |     79 | 60.5% | 39.5% |
|    1964 |    170 |    150 | 53.1%     |    190 |    210 | 47.5%     |     98 |     78 | 55.7% | 44.3% |
|    1963 |    169 |    151 | 52.8%     |    191 |    209 | 47.8%     |     97 |     79 | 55.1% | 44.9% |
|    1962 |    179 |    141 | 55.9%     |    181 |    219 | 45.3%     |    107 |     69 | 60.8% | 39.2% |
|    1961 |    162 |    154 | 51.3%     |    154 |    162 | 48.7%     |     84 |     76 | 52.5% | 47.5% |
|    1960 |    180 |    120 | 60.0%     |    120 |    180 | 40.0%     |    102 |     42 | 70.8% | 29.2% |
|    1959 |    159 |    129 | 55.2%     |    129 |    159 | 44.8%     |     87 |     57 | 60.4% | 39.6% |
|    1958 |    162 |    126 | 56.3%     |    126 |    162 | 43.8%     |     90 |     54 | 62.5% | 37.5% |
|    1957 |    155 |    133 | 53.8%     |    133 |    155 | 46.2%     |     83 |     61 | 57.6% | 42.4% |
|    1956 |    154 |    134 | 53.5%     |    134 |    154 | 46.5%     |     82 |     62 | 56.9% | 43.1% |
|    1955 |    150 |    138 | 52.1%     |    138 |    150 | 47.9%     |     78 |     66 | 54.2% | 45.8% |
+---------+--------+--------+-----------+--------+--------+-----------+--------+--------+-------+-------+
| year_id | east_w | east_l | east_wpct | west_w | west_l | west_wpct | e_vs_w | w_vs_e | e_h2h | w_h2h |
+---------+--------+--------+-----------+--------+--------+-----------+--------+--------+-------+-------+
|    1954 |    173 |    187 | 48.1%     |    151 |    137 | 52.4%     |     73 |     87 | 45.6% | 54.4% |
|    1953 |    168 |    183 | 47.9%     |    183 |    168 | 52.1%     |     67 |     82 | 45.0% | 55.0% |
|    1952 |    169 |    161 | 51.2%     |    161 |    169 | 48.8%     |     79 |     71 | 52.7% | 47.3% |
|    1951 |    181 |    187 | 49.2%     |    173 |    167 | 50.9%     |     80 |     86 | 48.2% | 51.8% |
+---------+--------+--------+-----------+--------+--------+-----------+--------+--------+-------+-------+

In the early stages of 2013-14, we are indeed seeing an historic level of inter-conference imbalance. The West's 70.8% winning percentage vs. the East is tied for the highest by one conference/division vs the other, matching the mark set by the Eastern Division in 1960.

Powered by the transcendent 59-16 Celtics (who won 10 more games than any other team), the 49-26 Philadelphia Warriors, and the 45-30 Syracuse Nationals, the East dominated a Western Division that boasted only one team -- the 46-29 St. Louis Hawks -- with a record anywhere near .500. (Aside from St. Louis, the other West teams had a combined 74-151 record that season.)

10 Responses to “Historical Western Conference vs Eastern Conference Disparity”

  1. Neil Says:

    Bizarre how the East & West flip-flopped in 1989 vs 1990. Initially I thought it was because the Celtics were declining & Bird missed an entire season, but 1989 (the year the East won nearly 60% of interconference games) was actually the season Bird was limited to just 6 games, leading to a down year in Boston. (Bird would return to play 75 games at an All-Star clip in 1990... the year the East won only 46% of interconference games.)

    Instead, the primary culprits were precipitous declines by Atlanta, Cleveland, and Milwaukee, combined with the rising Blazers and Spurs out West.

    As an aside, the 1989 Blazers suffered through one of the flukiest down years of any team ever, and were possibly the most talented sub-.500 team of all time. They had Drexler, Porter, and Kersey in their primes and had won 53 games the previous year, but practically everyone on the roster had a down year in '89 and they only went 39-43. The following season they returned much of the same cast (with the additions of Buck Williams and Clifford Robinson), winning 59 games and the conference title. They'd go on to win 63 and 57 in the following 2 seasons, making their 39-win '89 campaign stick out like a sore thumb.

  2. Jason J Says:

    God I love it when you blog basketball!

    Considering how good Indi and Miami are, it's even more preposterous that the rest of the East could be this sucktastic this year.

  3. Data shows historical disparity between Eastern, Western conferences | The Point Forward - SI.com Says:

    […] conferences that — if it continues apace — would be downright historic. According to data drudged up by Neil Paine of Sports-Reference, the West’s dominance over the East in win percentage is slated to be the greatest […]

  4. Ty Says:

    I'm surprised at the 1999 season, I would have thought the West would have dominated over the East (with the Bulls falling off). I think if there was a full season, it would have been more even. The East did have some teams that could compete with the West (Pacers, Heat, Knicks when they got healthier and more cohesive), and some West teams were declining or underachieving (Sonics, Lakers, Rockets).

    After the 1999 season, there was little doubt who the best conference was.

  5. Jacob Says:

    Three explanations for the disparity this year:

    1. The 00s bad apple teams out West (Clippers, Warriors, Wolves, Kings) all have new, enlightened management teams that have repaired the mistakes of their predecessors.

    2. Meanwhile, the 00s bad apple teams in the East (Knicks, Wizards, Nets, Bobcats) are under similar / worse management, and have generally doubled down on strategies that weren't working to begin with.

    3. In related news: Western teams have smoked Eastern teams during the 2005-2012 drafts, despite drafting lower on average.

  6. k Says:

    1999 is arguably the most screwed up season in NBA history. Totally unbalanced schedule, starting with interconference play. Interesting to note that the eventual champion Spurs had one of the easiest backend scheds in the league that year, which is when they took off.

  7. » The NBA’s Eastern Conference teams vs. Western Conference teams 1952-2013 Dataspam Says:

    […] Adapted from Neil’s Sports-Reference postRed is Western Conference dominance and blue is Eastern conference dominance. […]

  8. Adam Says:

    Hi, great post. I've taken the table data and made a visualization of the data so it's easier to see:

  9. Adam Says:

    http://oi41.tinypic.com/16bftp0.jpg

  10. Neil Says:

    #8 - Nice work -- what's your Twitter handle? I want to tweet this out