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RA versus ERA 1871-2010: Baseball Databank Data Dump 2.3.1

Ra_v_era_1871-2010_medium

I hate Earned Run Average. I doesn't add anything truly useful over Runs Allowed, unless you think that errors are a Really Good Stat. I mean, I guess they're better than Pitcher Wins or something, but... I don't even have the energy to get into it right now.  I'm not even talking about ERA vs. FIP, or DIPS or tRA or SIERA or anything like that. I just mean the "E" part of it. There are many, many good posts on why the "earned" rules is silly, for example this one by Jack Moore or this classic by Michael Wolverton, and I'm not going to get into it, here. Moreover, if you're, say, calculating pitcher WAR, for example, the ERA scale (with whatever statistics) will undervalue pitchers when compared to position players since you aren't comparing it to a "real" runs scale, the runs-to-win conversion is thrown off, and so forth. Sigh. However, I grant that it is still the most common pitching statistic, and most of the newer pitching stats are scaled to it (not because the creators "believe" in ERA, but because they understandably want to use a scale people are familiar with). But until That Great Day comes when ERA is banished and we're all on an RA scale, having a quick "scale" to convert from one to the other might be helpful.

That's right, it's time for another thrilling Baseball Databank Data Dump.

I decided to do this rather simple "dump" because I am thinking of doing a few slightly more involved pitching-related examples down the road. In the past, I've posted both RA and ERA scaled-stuff, but if a chart has more than a few columns, it really gets messed up. On one hand, I'm tempted just to go cold turkey and just post everything scaled to RA. On the other hand, despite my irritation with ERA and my thought that the best way to "cure" people of ERA is for all the stats sites to simply switch to using all RA-scale, all the time, I understand the difficulty of working against such a high coefficient of static friction involved. I haven't decided what I'm going to do in my future posts (and I do want to make them user-friendly for all 18 non-BtBS readers who persuse them).

If I do decide to go "all RA" or if you want the conversion or comparison for other reasons, here is the a table with the yearly list of major league-wide RA versus ERA from 1871 through 2010. As you can see., in recent seasons the "scale" of ERA divided RA has been about 0.92. So if you want to use an ERA-scaled stat in an RA fashion, a quick workaround is to divide it by 0.92. If you want to be more precise, you can use the specific conversion. The "Diff" column is, as you might expect, lgRA minus lgERA for each season. As you might surmise from the graph above as well as the table below, there's a pretty big "improvement" in the early part of the century. My assumption (I'm far from a historian of baseball) is that it's partly an improvement in fielding skills and positioning, but probably mostly improvements in glove design and playing-surface upkeep. It would be fun to have a discussion on those topics.

Hopefully this is useful, or at least interesting, to someone out there. As always, the source data is from the freely available Baseball Databank, another great resource proviced by Sean Forman.

 

RA and ERA, 1871-2010

Season

RA

ERA

Scale

Diff

2010

4.4284

4.0794

0.9212033

0.3489

2009

4.6629

4.3218

0.92684776

0.3411

2008

4.6881

4.3238

0.92229356

0.3643

2007

4.8335

4.4731

0.92543521

0.3604

2006

4.9099

4.5268

0.92198822

0.383

2005

4.6476

4.291

0.92326988

0.3566

2004

4.8482

4.4647

0.92090178

0.3835

2003

4.7722

4.4

0.92201236

0.3722

2002

4.6609

4.2788

0.91802035

0.3821

2001

4.8234

4.4175

0.91585844

0.4058

2000

5.197

4.7697

0.91778463

0.4273

1999

5.1426

4.7083

0.91555628

0.4343

1998

4.8213

4.4316

0.91915936

0.3898

1997

4.8064

4.3895

0.9132568

0.4169

1996

5.0661

4.6109

0.910166

0.4551

1995

4.8842

4.4515

0.91142477

0.4326

1994

4.9593

4.5116

0.90972575

0.4477

1993

4.6356

4.1906

0.90399732

0.445

1992

4.1256

3.7456

0.90790612

0.3799

1991

4.3194

3.9112

0.90550008

0.4082

1990

4.2933

3.8613

0.89938055

0.432

1989

4.1534

3.711

0.89347889

0.4424

1988

4.1526

3.7335

0.8990794

0.4191

1987

4.7624

4.2935

0.90152391

0.469

1986

4.4302

3.9727

0.89673767

0.4575

1985

4.3534

3.8936

0.89437857

0.4598

1984

4.2777

3.811

0.89091011

0.4667

1983

4.3328

3.8728

0.89383599

0.46

1982

4.303

3.8629

0.89773606

0.44

1981

3.9977

3.5835

0.89638468

0.4142

1980

4.2914

3.8419

0.89525287

0.4495

1979

4.4937

4.0029

0.89077112

0.4908

1978

4.1406

3.687

0.89044113

0.4536

1977

4.4841

3.9986

0.89171941

0.4855

1976

3.9921

3.5141

0.88026078

0.478

1975

4.2234

3.7105

0.8785517

0.5129

1974

4.1329

3.6273

0.87766422

0.5056

1973

4.2256

3.7459

0.88648021

0.4797

1972

3.6877

3.2639

0.88508682

0.4238

1971

3.9019

3.4688

0.88900683

0.4331

1970

4.3582

3.8859

0.89164692

0.4722

1969

4.0885

3.6131

0.8837224

0.4754

1968

3.42

2.9822

0.87199568

0.4378

1967

3.7654

3.3031

0.87723178

0.4623

1966

3.9974

3.5208

0.88077519

0.4766

1965

3.9926

3.4989

0.87633246

0.4938

1964

4.0536

3.5804

0.8832673

0.4732

1963

3.9519

3.459

0.87527387

0.4929

1962

4.4871

3.9553

0.88147431

0.5318

1961

4.5761

4.0274

0.88008036

0.5488

1960

4.3226

3.8171

0.88306452

0.5055

1959

4.4197

3.9041

0.88335023

0.5156

1958

4.3176

3.8605

0.89411987

0.4571

1957

4.284

3.8329

0.89469725

0.4511

1956

4.4933

3.9642

0.88224096

0.5291

1955

4.526

3.9993

0.88363899

0.5266

1954

4.4039

3.8971

0.88491734

0.5068

1953

4.6675

4.1377

0.88648696

0.5298

1952

4.1944

3.7028

0.88279061

0.4916

1951

4.5664

4.0392

0.88454029

0.5272

1950

4.9205

4.3586

0.88579039

0.562

1949

4.6644

4.1184

0.88294519

0.546

1948

4.642

4.1188

0.88728784

0.5232

1947

4.4217

3.8853

0.87867036

0.5365

1946

4.0455

3.4575

0.85464591

0.588

1945

4.2057

3.5823

0.85177616

0.6234

1944

4.1788

3.5205

0.84246575

0.6583

1943

3.8844

3.3332

0.85810322

0.5512

1942

4.0982

3.4845

0.8502401

0.6137

1941

4.5277

3.89

0.85915115

0.6377

1940

4.7221

4.1123

0.87087295

0.6097

1939

4.8946

4.2666

0.87169334

0.628

1938

4.9724

4.2826

0.86127361

0.6898

1937

4.9582

4.2651

0.8602204

0.6931

1936

5.2509

4.5229

0.86136381

0.728

1935

4.9479

4.2363

0.8561809

0.7116

1934

4.9715

4.2805

0.86100225

0.691

1933

4.5127

3.8067

0.84354795

0.706

1932

4.9238

4.1774

0.84840975

0.7464

1931

4.8674

4.1225

0.84696881

0.7449

1930

5.6354

4.81

0.85353203

0.8254

1929

5.2526

4.4754

0.85204642

0.7771

1928

4.7485

4.0087

0.84421288

0.7398

1927

4.8024

4.0234

0.83780332

0.7789

1926

4.7034

3.9202

0.83347887

0.7832

1925

5.1894

4.3266

0.83374374

0.8628

1924

4.7937

4.0463

0.84408694

0.7474

1923

4.8389

3.9882

0.82418323

0.8508

1922

4.9042

4.0647

0.82883481

0.8394

1921

4.8766

4.0311

0.82662305

0.8455

1920

4.3535

3.4572

0.7941313

0.8962

1919

3.8842

3.063

0.78859447

0.8211

1918

3.6111

2.7656

0.76585366

0.8455

1917

3.577

2.682

0.74977639

0.8951

1916

3.5522

2.7186

0.76533483

0.8336

1915

3.839

2.9013

0.75575097

0.9377

1914

3.9001

2.9069

0.74533434

0.9932

1913

4.0691

3.0642

0.75303197

1.0049

1912

4.5802

3.3664

0.73497979

1.2138

1911

4.5523

3.365

0.73919283

1.1873

1910

3.8585

2.7681

0.7173981

1.0904

1909

3.5682

2.5298

0.70898149

1.0384

1908

3.3991

2.3661

0.69609588

1.033

1907

3.5945

2.5025

0.69619091

1.092

1906

3.6832

2.6574

0.72149049

1.0258

1905

3.9483

2.8199

0.71419683

1.1284

1904

3.8072

2.6613

0.69901139

1.1459

1903

4.5396

3.1119

0.68550666

1.4277

1902

4.5168

3.1695

0.70171001

1.3473

1901

5.0976

3.4876

0.68416298

1.61

1900

5.3851

3.6966

0.68644639

1.6885

1899

5.4791

3.8485

0.70239453

1.6306

1898

5.1497

3.6029

0.69963851

1.5468

1897

6.1339

4.3079

0.70231092

1.826

1896

6.2487

4.3581

0.6974359

1.8906

1895

6.8593

4.7764

0.69633658

2.0829

1894

7.6555

5.313

0.69400685

2.3425

1893

6.696

4.6609

0.69607368

2.0351

1892

5.2458

3.2845

0.62611845

1.9613

1891

5.8506

3.5315

0.60361569

2.3191

1890

6.1883

3.8818

0.6272826

2.3065

1889

6.1458

3.9319

0.63977211

2.2139

1888

4.9631

2.9455

0.59348522

2.0176

1887

6.5734

4.1727

0.63479168

2.4007

1886

5.6707

3.3702

0.59432242

2.3005

1885

5.3197

3.032

0.56995265

2.2877

1884

5.568

3.1073

0.55806839

2.4607

1883

5.857

3.2171

0.54928018

2.6399

1882

5.4041

2.8036

0.51878589

2.6005

1881

5.1499

2.7749

0.53882078

2.375

1880

4.7616

2.3741

0.49858978

2.3875

1879

5.2926

2.4965

0.47169258

2.7961

1878

5.1552

2.3041

0.44695378

2.8511

1877

5.6649

2.8075

0.49558824

2.8575

1876

5.8147

2.3073

0.39679948

3.5075

1875

6.1537

2.4592

0.39962211

3.6946

1874

7.4844

3.0175

0.40317003

4.4669

1873

8.9883

3.2513

0.36173184

5.7369

1872

9.284

3.7174

0.4004131

5.5666

1871

10.636

4.22

0.3967657

6.416