Be careful with Calculated Columns or you may end up with the wrong results.  Take the following set of data (below). If you use a Calculated Column "wp", then you will get the wrong results if you wish to calculate the total win percentage for a coach. This can be seen in a Matrix of Coach, Season and "wp" or if you ask Q&A in Power BI. To get the correct answer, use a Calculated Field instead with a formula of WinningPercentage:=SUM([Wins])/SUM([Games]).

For example, a matrix of Power BI will tell you that the overall "wp" for Earle Bruce is 74.79%. However, Earle won 81 games out of 108 games and thus his true "wp" is 75% (81 / 108).  The Calculated Field gets it right while the Calculated Column gets it wrong. However, for individual years, both the Calculated Column "wp" and Calculated Field "WinningPercentage" agree.

What is going on? Well, in a matrix using average of a Calculated Column, "wp", the "Total" row in the matrix is actually average of the individual rows while with a Calculated Field, "WinningPercentage" it is the result of the formula for that particular row. In the total line, the numbers used by the Calculated Field are 108 for games and 81 for Wins and thus it calculates the correct answer.

The following data can be used to recreate this scenario.

 

Season Wins Losses Ties Coach Conference Bowl Game Games wp
2012 12 0 0 Urban Meyer Big Ten 12 100.00 %
1999 6 6 0 John Cooper Big Ten 12 50.00 %
1988 4 6 1 John Cooper Big Ten 11 36.36 %
1987 6 4 1 Earle Bruce Big Ten 11 54.55 %
1971 6 4 0 Woody Hayes Big Ten 10 60.00 %
1969 8 1 0 Woody Hayes Big Ten 9 88.89 %
1967 6 3 0 Woody Hayes Big Ten 9 66.67 %
1966 4 5 0 Woody Hayes Big Ten 9 44.44 %
1965 7 2 0 Woody Hayes Big Ten 9 77.78 %
1964 7 2 0 Woody Hayes Big Ten 9 77.78 %
1963 5 3 1 Woody Hayes Big Ten 9 55.56 %
1962 6 3 0 Woody Hayes Big Ten 9 66.67 %
1961 8 0 1 Woody Hayes Big Ten 9 88.89 %
1960 7 2 0 Woody Hayes Big Ten 9 77.78 %
1959 3 5 1 Woody Hayes Big Ten 9 33.33 %
1958 6 1 2 Woody Hayes Big Ten 9 66.67 %
1956 6 3 0 Woody Hayes Big Ten 9 66.67 %
1955 7 2 0 Woody Hayes Big Ten 9 77.78 %
1953 6 3 0 Woody Hayes Big Ten 9 66.67 %
1952 6 3 0 Woody Hayes Big Ten 9 66.67 %
1951 4 3 2 Woody Hayes Big Ten 9 44.44 %
1950 6 3 0 Wes Fesler Big Ten 9 66.67 %
1948 6 3 0 Wes Fesler Big Ten 9 66.67 %
1947 2 6 1 Wes Fesler Big Ten 9 22.22 %
1946 4 3 2 Paul Bixler Big Ten 9 44.44 %
1945 7 2 0 Carroll Widdoes Big Ten 9 77.78 %
1944 9 0 0 Carroll Widdoes Big Ten 9 100.00 %
1943 3 6 0 Paul Brown Big Ten 9 33.33 %
1942 9 1 0 Paul Brown Big Ten 10 90.00 %
1941 6 1 1 Paul Brown Big Ten 8 75.00 %
1940 4 4 0 Francis Schmidt Big Ten 8 50.00 %
1939 6 2 0 Francis Schmidt Big Ten 8 75.00 %
1938 4 3 1 Francis Schmidt Big Ten 8 50.00 %
1937 6 2 0 Francis Schmidt Big Ten 8 75.00 %
1936 5 3 0 Francis Schmidt Big Ten 8 62.50 %
1935 7 1 0 Francis Schmidt Big Ten 8 87.50 %
1934 7 1 0 Francis Schmidt Big Ten 8 87.50 %
1933 7 1 0 Sam Willaman Big Ten 8 87.50 %
1932 4 1 3 Sam Willaman Big Ten 8 50.00 %
1931 6 3 0 Sam Willaman Big Ten 9 66.67 %
1930 5 2 1 Sam Willaman Big Ten 8 62.50 %
1929 4 3 1 Sam Willaman Big Ten 8 50.00 %
1928 5 2 1 John Wilce Big Ten 8 62.50 %
1927 4 4 0 John Wilce Big Ten 8 50.00 %
1926 7 1 0 John Wilce Big Ten 8 87.50 %
1925 4 3 1 John Wilce Big Ten 8 50.00 %
1924 2 3 3 John Wilce Big Ten 8 25.00 %
1923 3 4 1 John Wilce Big Ten 8 37.50 %
1922 3 4 0 John Wilce Big Ten 7 42.86 %
1921 5 2 0 John Wilce Ohio Athletic 7 71.43 %
1919 6 1 0 John Wilce Ohio Athletic 7 85.71 %
1918 3 3 0 John Wilce Ohio Athletic 6 50.00 %
1917 8 0 1 John Wilce Ohio Athletic 9 88.89 %
1916 7 0 0 John Wilce Ohio Athletic 7 100.00 %
1915 5 1 1 John Wilce Ohio Athletic 7 71.43 %
1914 5 2 0 John Wilce Ohio Athletic 7 71.43 %
1913 4 2 1 John Wilce Ohio Athletic 7 57.14 %
1912 6 3 0 John Richards Ohio Athletic 9 66.67 %
1911 5 3 2 Harry Vaughn Ohio Athletic 10 50.00 %
1910 6 1 3 Howard Jones Ohio Athletic 10 60.00 %
1909 7 3 0 Albert Herrnstein Ohio Athletic 10 70.00 %
1908 6 4 0 Albert Herrnstein Ohio Athletic 10 60.00 %
1907 7 2 1 Albert Herrnstein Ohio Athletic 10 70.00 %
1906 8 1 0 Albert Herrnstein Ohio Athletic 9 88.89 %
1905 8 2 2 ER Sweetland Ohio Athletic 12 66.67 %
1904 6 5 0 ER Sweetland Ohio Athletic 11 54.55 %
1903 8 3 0 Perry Hale Ohio Athletic 11 72.73 %
1902 6 2 2 Perry Hale Ohio Athletic 10 60.00 %
1901 5 3 1 John Eckstorm Independent 9 55.56 %
1900 8 1 1 John Eckstorm Independent 10 80.00 %
1899 9 0 1 John Eckstorm Independent 10 90.00 %
1898 3 5 0 Jack Ryder Independent 8 37.50 %
1897 1 8 0 David Edwards Independent 9 11.11 %
1896 5 5 1 Charles Hickey Independent 11 45.45 %
1895 4 4 2 Jack Ryder Independent 10 40.00 %
1894 5 6 0 Jack Ryder Independent 11 45.45 %
1893 4 5 0 Jack Ryder Independent 9 44.44 %
1892 5 3 0 Jack Ryder Independent 8 62.50 %
1891 2 2 0 Alexander Lilley Independent 4 50.00 %
1890 1 3 0 Alexander Lilley Independent 4 25.00 %
2014 14 1 0 Urban Meyer Big Ten Sugar Bowl 15 93.33 %
2013 12 2 0 Urban Meyer Big Ten Orange Bowl 14 85.71 %
2011 6 7 0 Luke Fickell Big Ten Gator Bowl 13 46.15 %
2010 12 1 0 Jim Tressel Big Ten Sugar Bowl 13 92.31 %
2009 11 2 0 Jim Tressel Big Ten Rose Bowl 13 84.62 %
2008 10 3 0 Jim Tressel Big Ten Fiesta Bowl 13 76.92 %
2007 11 2 0 Jim Tressel Big Ten BCS National Championship 13 84.62 %
2006 12 1 0 Jim Tressel Big Ten BCS National Championship 13 92.31 %
2005 10 2 0 Jim Tressel Big Ten Fiesta Bowl 12 83.33 %
2004 8 4 0 Jim Tressel Big Ten Alamo Bowl 12 66.67 %
2003 11 2 0 Jim Tressel Big Ten Fiesta Bowl 13 84.62 %
2002 14 0 0 Jim Tressel Big Ten Fiesta Bowl 14 100.00 %
2001 7 5 0 Jim Tressel Big Ten Outback Bowl 12 58.33 %
2000 8 4 0 John Cooper Big Ten Outback Bowl 12 66.67 %
1998 11 1 0 John Cooper Big Ten Sugar Bowl 12 91.67 %
1997 10 3 0 John Cooper Big Ten Sugar Bowl 13 76.92 %
1996 11 1 0 John Cooper Big Ten Rose Bowl 12 91.67 %
1995 11 2 0 John Cooper Big Ten Citrus Bowl 13 84.62 %
1994 9 4 0 John Cooper Big Ten Florida Citrus Bowl 13 69.23 %
1993 10 1 1 John Cooper Big Ten Holiday Bowl 12 83.33 %
1992 8 3 1 John Cooper Big Ten Florida Citrus Bowl 12 66.67 %
1991 8 4 0 John Cooper Big Ten Hall of Fame Bowl 12 66.67 %
1990 7 4 1 John Cooper Big Ten Liberty Bowl 12 58.33 %
1989 8 4 0 John Cooper Big Ten Hall of Fame Bowl 12 66.67 %
1986 10 3 0 Earle Bruce Big Ten Cotton Bowl 13 76.92 %
1985 9 3 0 Earle Bruce Big Ten Florida Citrus Bowl 12 75.00 %
1984 9 3 0 Earle Bruce Big Ten Rose Bowl 12 75.00 %
1983 9 3 0 Earle Bruce Big Ten Fiesta Bowl 12 75.00 %
1982 9 3 0 Earle Bruce Big Ten Holiday Bowl 12 75.00 %
1981 9 3 0 Earle Bruce Big Ten Liberty Bowl 12 75.00 %
1980 9 3 0 Earle Bruce Big Ten Fiesta Bowl 12 75.00 %
1979 11 1 0 Earle Bruce Big Ten Rose Bowl 12 91.67 %
1978 7 4 1 Woody Hayes Big Ten Gator Bowl 12 58.33 %
1977 9 3 0 Woody Hayes Big Ten Sugar Bowl 12 75.00 %
1976 9 2 1 Woody Hayes Big Ten Orange Bowl 12 75.00 %
1975 11 1 0 Woody Hayes Big Ten Rose Bowl 12 91.67 %
1974 10 2 0 Woody Hayes Big Ten Rose Bowl 12 83.33 %
1973 10 0 1 Woody Hayes Big Ten Rose Bowl 11 90.91 %
1972 9 2 0 Woody Hayes Big Ten Rose Bowl 11 81.82 %
1970 9 1 0 Woody Hayes Big Ten Rose Bowl 10 90.00 %
1968 10 0 0 Woody Hayes Big Ten Rose Bowl 10 100.00 %
1957 9 1 0 Woody Hayes Big Ten Rose Bowl 10 90.00 %
1954 10 0 0 Woody Hayes Big Ten Rose Bowl 10 100.00 %
1949 7 1 2 Wes Fesler Big Ten Rose Bowl 10 70.00 %
1920 7 1 0 John Wilce Ohio Athletic Rose Bowl 8 87.50 %