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  • gje627

    Bristol Motor Speedway — “The World’s Fastest Half Mile”, “Thunder Valley”, “The Last Great Colosseum”, “The Bullring”

    Schedule — all times are Eastern Time (ET)

    Practice 1: Friday, August 16, 11:05-11:55 AM (NBCSN)
    Practice 2: Friday, August 16, 1:05-1:55 PM (NBCSN)
    Qualifying: Friday, August 16, 5:35 PM (NBCSN)
    Technical Inspection: Saturday, August 17, 2:00 PM (No TV)
    Race: Saturday, August 17, 7:46 PM (NBCSN); Lineup Lock 7:30 PM

    Inspection Protocol

    Impound Race: Cars will be inspected prior to race.

    Fail 1st Time: Qualifying time disallowed; car/driver start at the rear. Driver scored from the rear and not from starting position based on qualifying. Fail 2nd Time: + Pit crew member ejected for race. Fail 3rd Time: ++ Driver will pass through pit row on Lap 1 (more than likely Lap 2). At Bristol this is a significant penalty since it is a short track.

    Note: If multiple cars fail (i.e. go to the back), the starting positions of cars going to the back is set by owner points and not driver points. For most cars this is the same; however for teams that employ different drivers for different races this may be relevant (see Rick Ware Racing). The difference between owner points and driver points is that owner points are simply the points attached to a car number and driver points are attached to a driver. Pretty sure everyone here knows this already, but on the off-chance someone does not … this is the explanation.

    Race Details

    — 39 Drivers Entered; 500 Laps, 266.5 Miles
    — Stage 1: Lap 1 – 125; Stage 2: Lap 126 – 250; Stage 3: Lap 251 – 500
    — Expected Fuel Window – 170-180 Laps.

    Note: fuel window, fuel cell capacity is an estimate as of 8/12/2019.

    Fantasy Relevant Track Details/Rankings 2005 to 2019 (29 Races), 24 Tracks (Charlotte Motor Speedway and Charlotte ROVAL considered 2 Different Tracks)

    — 0.533 mile Short-Track Oval. 24 to 30 degree banking in turns, 6 to 10 degree banking in straights. Straights 650 long, 40 feet wide.
    — Winner Average Margin of Victory: 0.912 seconds; Low – 0.064 seconds (2007 – Race #1); High – 4.652 seconds (2005 – Race #1); Finishes under caution 2014, Race #1.
    — Rank Most Green Flag Passes: 10 of 24 Tracks (15.78 Green Flag Passes per 100 Miles)
    — Rank Most Quality Passes (Top 15 Passes): 3 of 24 Tracks (6.80 Quality Passes per 100 Miles)
    — Rank Most Lead Changes: 4 of 24 Tracks (6.36 Lead Changes per 100 Miles)
    — Rank Most Cautions: 2 of 24 Tracks (3.97 Cautions per 100 Miles)
    — Rank Highest % Drivers Finishing on Lead Lap: 23 of 24 Tracks (39.07% per Drivers/Race)
    — Rank Highest % DNF Drivers – Mechanical: 20 of 24 Tracks (6.72% per Drivers/Race)
    — Rank Highest % DNF Drivers – Crash: 5 of 24 Tracks (8.35% per Drivers/Race)
    — Rank Highest % DNF Drivers – Overall: 10 of 24 Tracks (15.07% per Drivers/Race)

    Note: Data and Rankings are Cup series only. Green Flag Passes, Quality Passes standardized to 100 miles per driver to account for differences in miles per race and number of drivers in field. Lead Changes and Cautions standardized to 100 miles for entire field. Lead Lap and all DNF categories standardized to drivers per race. All statistics updated through most recent race (Michigan International Speedway, 8/11/2019).

    Comparable Tracks (alphabetical order)

    Darlington Raceway, Dover International Speedway, Homestead-Miami Speedway, Las Vegas Motor Speedway.

    Note: For fantasy and analytical purposes Bristol really is a unique track. For analytical purposes, Dover International Speedway is the most comparable, but this is still somewhat of a stretch.

    Last Six (6) Race Winners

    — 2016-23: Kevin Harvick (start 24)
    — 2017-08: Jimmie Johnson (start 11)
    — 2017-24: Kyle Busch (start 18)
    — 2018-08: Kyle Busch (start 1)
    — 2018-24: Kurt Busch (start 9)
    — 2019-08: Kyle Busch (start 17)

    Last Six (6) DK and FD Fantasy Points Leaders

    2016-23 Kevin Harvick (DK FPts 133.50) — Kevin Harvick (FD FPts 117.3)
    2017-08 Kyle Larson (DK FPts 110.50) — Jimmie Johnson (FD FPts 106.1)
    2017-24 Kyle Busch (DK FPts 145.00) — Kyle Busch (FD FPts 117.1)
    2018-08 Kyle Larson (DK FPts 150.50) — Kyle Larson (FD FPts 112)
    2018-24 Clint Bowyer (DK FPts 96.00) — Joey Logano (FD FPts 104)
    2019-08 Joey Logano (DK FPts 117.00) — Kyle Busch (FD FPts 108.1)

    Data and Analytics Links – Archived, 8/19/2019, 8:12 AM MT

    Pre-Race

    DK and FD Base Points Grid
    DK and FD Projections — Base and Dominator
    Start Position Analysis — DK Only
    DK and FD Minimum Projected FPts Needed to Cash and Win — GPP Only
    Practice through Qualifying, Including 10-Lap Averages
    Bristol Qualifying Position and Owner Points

    Post-Race

    DK and FD Driver FPts and Top 500 Optimal Lineups

    Race Data, News, and Information

    Stevie’s NASCAR Package
    Jayski
    Motor Racing Network
    Racing Reference

    Race Day Breaking News and Weather

    Stephen Young Twitter – stevietpfl
    Bob Pockrass Twitter
    NASCAR Weather

    Note: As needed information above will be updated.

    Any errors and/or omissions above are mine and mine only. If someone identifies an error, please respond by posting a comment and I will correct.

  • gje627

    Note: This past week someone requested some data. Always obliging, I thought it would be easiest to start this thread this week to share with everyone. Per above, data (more accurately analytics will be added later, periodically as I have time this week).

    For simplicity, the header above replicates the format I started last year …. Sorry if it sucks.

    Finally, I hope I didn’t step on any toes this week by starting this thread. If so, sorry and no need to worry as I really have no desire to start this thread on a regular basis.

    Peace Out :)

  • gvn2fly1421

    If I am understanding this correctly –

    “— Technical Inspection: Saturday, August 17, 2:00 PM (No TV)
    — Race: Saturday, August 17, 7:46 PM (NBCSN); Lineup Lock 7:30 PM”

    It seems it leaves a very small window to set/adjust lineups on Saturday? Thinking about it, I guess that is how most of these impound races are as far as time wise. Sunday morning tech, Sunday afternoon race.

  • jt77316

    Came here to make the thread and saw you had made it. Works for me! Glad to have you back, even if temporarily!

    For anyone interested (data from the last 5):

    Driver Rating:

    1. Kyle Larson – 108.9
    2. Joey Logano – 108.8
    3. Kyle Busch – 108.3
    4. Jimmie Johnson – 102.8
    5. Kevin Harvick – 97.0

    Laps Led:

    1. Kyle Larson – 489
    2. Ryan Blaney – 379
    3. Kyle Busch – 344
    4. Joey Logano – 314
    5. Erik Jones – 270

    Fastest Laps:

    1. Kyle Busch – 254
    2. Kyle Larson – 248
    3. Kevin Harvick – 194
    4. Erik Jones – 132
    5. Joey Logano – 132

  • gje627

    Below, please find the Spearman’s correlation coefficients for certain pre-race predictors of DK fantasy points. Importantly, these are predictors for individual drivers only and not a full 6-driver lineup. Also, importantly the coefficients include all DK fantasy points ranks and not only the top 6, top 10, etc. Finally, please note there is virtually no correlation between start position and DK fantasy performance. If you recall, last raced I mentioned start position was the single best predictor of fantasy scores. The reason that this doesn’t hold true below is, again, the below variables are for individuals and not a 6-driver lineup as a whole. Per the discussion this past Sunday, start position was determined the most important for a whole lineup.

    Bristol Motor Speedway, Cup Series – Pre-Race Predictors of DK Fantasy Points Performance – Spearman’s Rank Correlation (n = 29)

    Previous Finish Positions: 0.906
    Previous Avg Run Positions 0.731
    Previous Driver Ratings 0.716
    Current High Practice 0.250
    Previous Start Positions 0.135

    Key

    –1.000 – A perfect downhill (negative) relationship
    –0.700 – A strong downhill (negative) relationship
    –0.500 – A moderate downhill (negative) relationship
    –0.300 – A weak downhill (negative) relationship
    0.000 – No relationship
    +0.300 – A weak uphill (positive) relationship
    +0.500 – A moderate uphill (positive) relationship
    +0.700 – A strong uphill (positive) relationship
    +1.000 – A perfect uphill (positive) relationship

    Note: Unlike Pearson’s Correlation Coefficient, Spearman’s Rank Correlation does not measure linearity.

  • Zwalt83

    Do you think Larson his Chalk Here no matter the position, what happened the last time they raced here he finished 19th at this track last time Crash?

  • gje627

    Below, please find DK distribution for total fantasy points earned by the Top 6 fantasy scoring drivers, per track. Importantly, the data below is salary agnostic; i.e. there is high likelihood that you would not be to roster the top 6 fantasy scorers in the same lineup due to salary constraints. This was necessary to ensure a sufficient size since most races included in the numbers were pre-Draftkings NASCAR. Finally, the two tables below represent the same same data. Due to space/column width limitations percentages and ranks were separated into 2 tables.

    EDIT 1: There 5 columns in the tables below. If all 5 columns are not visible, zoom-out until you can see each column. Finally, sorry about the “messy” tables.

    EDIT 2: Numbers for Charlotte ROVAL are pretty much “whatever” since only 1 race has been run on this course configuration.

    —-

    2005 – 2019 DK % Fantasy Point Distribution for Top 6 Drivers by Track

    Track Fin Pos FPts % of Total Place Diff FPts % of Total Fast Laps FPts % of Total Laps Led FPts % of Total
    —————————- ———————- ———————- ———————- ——————-
    Atlanta 52.33% 15.60% 17.15% 14.92%
    Auto Club 58.38% 18.11% 13.42% 10.09%
    Bristol 45.98% 13.09% 21.14% 19.79%
    Charlotte 51.95% 14.35% 19.14% 14.56%
    Charlotte ROVAL 73.46% 24.01% 1.30% 1.23%
    Chicagoland 55.59% 15.40% 16.81% 12.19%
    Darlington 52.23% 12.04% 19.25% 16.48%
    Daytona 59.06% 32.72% 3.27% 4.95%
    Dover 48.50% 11.49% 21.95% 18.06%
    Homestead 55.60% 15.97% 15.66% 12.77%
    Indianapolis 63.12% 19.86% 9.89% 7.13%
    Kansas 55.96% 16.05% 15.78% 12.21%
    Kentucky 56.51% 11.24% 18.48% 13.77%
    Las Vegas 55.76% 15.63% 16.00% 12.61%
    Martinsville 45.72% 11.18% 22.40% 20.70%
    Michigan 60.83% 19.09% 11.70% 8.37%
    New Hampshire 54.79% 13.44% 18.39% 13.37%
    Phoenix 53.99% 13.08% 18.52% 14.40%
    Pocono 63.75% 16.76% 11.00% 8.49%
    Richmond 49.66% 11.25% 20.28% 18.81%
    Sonoma 64.05% 26.06% 5.12% 4.78%
    Talladega 60.48% 32.05% 3.33% 4.15%
    Texas 52.47% 15.30% 17.56% 14.67%
    Watkins Glen 69.28% 19.82% 6.28% 4.62%

    2005 – 2019 DK % Fantasy Point Distribution for Top 6 Drivers by Track — Ranked

    Track Fin Pos FPts Rank Place Diff FPts Rank Fast Laps FPts Rank Laps Led FPts Rank
    ————————— ———————- ———————- ———————- ———————-
    Atlanta 18 13 11 6
    Auto Club 9 8 16 16
    Bristol 23 18 3 2
    Charlotte 20 16 6 8
    Charlotte ROVAL 1 4 24 24
    Chicagoland 14 14 12 15
    Darlington 19 20 5 5
    Daytona 8 1 23 20
    Dover 22 21 2 4
    Homestead 13 11 15 12
    Indianapolis 5 5 19 19
    Kansas 11 10 14 14
    Kentucky 10 23 8 10
    Las Vegas 12 12 13 13
    Martinsville 24 24 1 1
    Michigan 6 7 17 18
    New Hampshire 15 17 9 11
    Phoenix 16 19 7 9
    Pocono 4 9 18 17
    Richmond 21 22 4 3
    Sonoma 3 3 21 21
    Talladega 7 2 22 23
    Texas 17 15 10 7
    Watkins Glen 2 6 20 22

    —-
    —-

  • Toddalan2286

    @gje627 said...

    Below, please find DK distribution for total fantasy points earned by the Top 6 fantasy scoring drivers, per track. Importantly, the data below is salary agnostic; i.e. there is high likelihood that you would not be to roster the top 6 fantasy scorers in the same lineup due to salary constraints. This was necessary to ensure a sufficient size since most races included in the numbers were pre-Draftkings NASCAR. Finally, the two tables below represent the same same data. Due to space/column width limitations percentages and ranks were separated into 2 tables.

    EDIT 1: There 5 columns in the tables below. If all 5 columns are not visible, zoom-out until you can see each column. Finally, sorry about the “messy” tables.

    EDIT 2: Numbers for Charlotte ROVAL are pretty much “whatever” since only 1 race has been run on this course configuration.

    —-

    2005 – 2019 DK % Fantasy Point Distribution for Top 6 Drivers by Track

    Track Fin Pos FPts % of Total Place Diff FPts % of Total Fast Laps FPts % of Total Laps Led FPts % of Total
    —————————- ———————- ———————- ———————- ——————-
    Atlanta 52.33% 15.60% 17.15% 14.92%
    Auto Club 58.38% 18.11% 13.42% 10.09%
    Bristol 45.98% 13.09% 21.14% 19.79%
    Charlotte 51.95% 14.35% 19.14% 14.56%
    Charlotte ROVAL 73.46% 24.01% 1.30% 1.23%
    Chicagoland 55.59% 15.40% 16.81% 12.19%
    Darlington 52.23% 12.04% 19.25% 16.48%
    Daytona 59.06% 32.72% 3.27% 4.95%
    Dover 48.50% 11.49% 21.95% 18.06%
    Homestead 55.60% 15.97% 15.66% 12.77%
    Indianapolis 63.12% 19.86% 9.89% 7.13%
    Kansas 55.96% 16.05% 15.78% 12.21%
    Kentucky 56.51% 11.24% 18.48% 13.77%
    Las Vegas 55.76% 15.63% 16.00% 12.61%
    Martinsville 45.72% 11.18% 22.40% 20.70%
    Michigan 60.83% 19.09% 11.70% 8.37%
    New Hampshire 54.79% 13.44% 18.39% 13.37%
    Phoenix 53.99% 13.08% 18.52% 14.40%
    Pocono 63.75% 16.76% 11.00% 8.49%
    Richmond 49.66% 11.25% 20.28% 18.81%
    Sonoma 64.05% 26.06% 5.12% 4.78%
    Talladega 60.48% 32.05% 3.33% 4.15%
    Texas 52.47% 15.30% 17.56% 14.67%
    Watkins Glen 69.28% 19.82% 6.28% 4.62%

    *2005 – 2019 DK % Fantasy Point Distribution for Top 6 Drivers by Track — Ranked

    Track Fin Pos FPts Rank Place Diff FPts Rank Fast Laps FPts Rank Laps Led FPts Rank
    ————————— ———————- ———————- ———————- ———————-
    Atlanta 18 13 11 6
    Auto Club 9 8 16 16
    Bristol 23 18 3 2
    Charlotte 20 16 6 8
    Charlotte ROVAL 1 4 24 24
    Chicagoland 14 14 12 15
    Darlington 19 20 5 5
    Daytona 8 1 23 20
    Dover 22 21 2 4
    Homestead 13 11 15 12
    Indianapolis 5 5 19 19
    Kansas 11 10 14 14
    Kentucky 10 23 8 10
    Las Vegas 12 12 13 13
    Martinsville 24 24 1 1
    Michigan 6 7 17 18
    New Hampshire 15 17 9 11
    Phoenix 16 19 7 9
    Pocono 4 9 18 17
    Richmond 21 22 4 3
    Sonoma 3 3 21 21
    Talladega 7 2 22 23
    Texas 17 15 10 7
    Watkins Glen 2 6 20 22

    Wonder what the correlation looks like for fastest laps in race vs various practice ranks at Bristol?

  • gje627

    @Toddalan2286 said...

    Wonder what the correlation looks like for fastest laps in race vs various practice ranks at Bristol?

    Me too !!!

    Let me know when you find out !!! :)

    Just Kidding

    Importantly, remember this for a group of 6 drivers, and not for drivers individually. Further, the group of 6 is Top 6.

    Interestingly, this is the second shortest track on the circuit (Martinsville being slightly shorter), and steep-banked in the corners, running 750 HP ….

    What does this mean, off-throttle time is huge here even with the steep banks, and the field will be a muddled mess with cars stacked/crowded all over the track ….

    Meaning fast laps during the race are really spread-out across multiple drivers, as certain fast cars hit lap traffic and/or slower cars while other cars have a free window of space for a lap or two.

    The long-and-the-short, like the correlations I posted above, I doubt practice speed is a good indicator of race speed.

  • Moszman

    Love Bristol, thanks for taking the time to post info.

  • gje627

    Update: 8/13/2019, 8:12 MT Deleted the Rotogrinders NASCAR Free Tools link in header. I haven’t clicked on it in ages (at least a year) but did tonight, and RG is no longer updating the data on that page and the current data there is very, very old (yes, older than dust).

    Question: Is everyone here familiar with the Base Points scoring grid used to quickly visualize and cross reference the total fantasy base fantasy points for a driver starting at a certain position and finishing at a certain position? The grid essentially sums finishing position fantasy points + place differential fantasy points, again … given a specific starting position and an expected finishing position?

    Anyways, if you don’t know what I’m talking about it’s very helpful. The reason I haven’t posted previously is that I can do all this easier with a script in Python, so I forgot I even had it ….

    So … if anyone wants the grid for both DK and FD, I can post in the data section in the header. I calculated it myself so I wouldn’t be surprised if others have as well …. Nonetheless, it’s an Excel file (2 worksheets, one for DK and FD) and I can post a link if anyone needs it. Just reply with a yes and if more than 1 person wants I will link.

    EDIT: Wow my question above is super-redundant, but hopefully you get my point ….

  • starstx

    Ah gje … great to have you back … the plethora of information you provide is 2nd to none … now whether my bird brain can absorb it all is another story! And yes … I have been waiting to use plethora in a sentence for quite awhile

  • starstx

    I have been wondering how much weight I should be putting on practice times compared to other data like track history etc. I know above you said for Bristol practice speeds may not be a good indicator for race speed but in general. It has definitely helped me identify some fast cars and been fairly accurate but the data can be a little muddled. I have mainly looked at best 1 lap speed and 10 lap average for the final practice. And check the practice before to try to fill any gaps. Right now I weight it fairly heavily but feel I may be overweighting it.

  • stevietpfl

    Morning Grind co-host, Lead NASCAR Analyst

    • 183

      RG Overall Ranking

    • Ranked #29

      RG Tiered Ranking

    • 2015 FanDuel MLB Playboy Mansion Finalist

    • 2015 FAWBC Finalist

    @starstx said...

    I have been wondering how much weight I should be putting on practice times compared to other data like track history etc. I know above you said for Bristol practice speeds may not be a good indicator for race speed but in general. It has definitely helped me identify some fast cars and been fairly accurate but the data can be a little muddled. I have mainly looked at best 1 lap speed and 10 lap average for the final practice. And check the practice before to try to fill any gaps. Right now I weight it fairly heavily but feel I may be overweighting it.

    With NASCAR.com posting 5, 10, 15, 20, and 30 lap data, you can really see a few things with practice more than just looking at the 1 and 10 lap data now.

  • stevietpfl

    Morning Grind co-host, Lead NASCAR Analyst

    • 183

      RG Overall Ranking

    • Ranked #29

      RG Tiered Ranking

    • 2015 FanDuel MLB Playboy Mansion Finalist

    • 2015 FAWBC Finalist

    @gje627 said...

    Update: 8/13/2019, 8:12 MT Deleted the Rotogrinders NASCAR Free Tools link in header. I haven’t clicked on it in ages (at least a year) but did tonight, and RG is no longer updating the data on that page and the current data there is very, very old (yes, older than dust).

    We moved a lot of this data to the NASCAR premium, and a lot of the data is worthless with the new package so we stopped providing it this season.

  • starstx

    @stevietpfl said...

    With NASCAR.com posting 5, 10, 15, 20, and 30 lap data, you can really see a few things with practice more than just looking at the 1 and 10 lap data now.

    Thanks for the info … I need to start looking at this a little closer then

  • wscooby

    Yes! Please for at least DK.

  • wscooby

    @gje627 said...

    Update: 8/13/2019, 8:12 MT Deleted the Rotogrinders NASCAR Free Tools link in header. I haven’t clicked on it in ages (at least a year) but did tonight, and RG is no longer updating the data on that page and the current data there is very, very old (yes, older than dust).

    Question: Is everyone here familiar with the Base Points scoring grid used to quickly visualize and cross reference the total fantasy base fantasy points for a driver starting at a certain position and finishing at a certain position? The grid essentially sums finishing position fantasy points + place differential fantasy points, again … given a specific starting position and an expected finishing position?

    Anyways, if you don’t know what I’m talking about it’s very helpful. The reason I haven’t posted previously is that I can do all this easier with a script in Python, so I forgot I even had it ….

    So … if anyone wants the grid for both DK and FD, I can post in the data section in the header. I calculated it myself so I wouldn’t be surprised if others have as well …. Nonetheless, it’s an Excel file (2 worksheets, one for DK and FD) and I can post a link if anyone needs it. Just reply with a yes and if more than 1 person wants I will link.

    EDIT: Wow my question above is super-redundant, but hopefully you get my point ….

    Yes, please, for DK. Thank You.

  • garyb

    Yes please for DK

  • gje627

    Thanks for the positive feedback everyone !!!

    I posted the Draftkings and FanDuel Base Points grids. The link can be found in the Data and Analytics Links section of the header. Two tabs, one each for Draftkings and FanDuel. To download, simply click the three dots (periods) in the upper right of the page and select download.

  • Toddalan2286

    @starstx said...

    I have been wondering how much weight I should be putting on practice times compared to other data like track history etc. I know above you said for Bristol practice speeds may not be a good indicator for race speed but in general. It has definitely helped me identify some fast cars and been fairly accurate but the data can be a little muddled. I have mainly looked at best 1 lap speed and 10 lap average for the final practice. And check the practice before to try to fill any gaps. Right now I weight it fairly heavily but feel I may be overweighting it.

    Below are the correlations coefficients for final practice vs fast laps in the spring Bristol race.

    P3 single lap: -54025
    P3 10 Lap: -.61313

    *a negative coefficient means as practice rank decreases fast laps increase or vice versa.

    With those numbers it’d be hard for me NOT to consider practice speeds relevant. It will be interesting to see if the trend from single lap to 10 lap continues now that we can easily track 15, 20, 25, and 30 lap.

  • gje627

    @Toddalan2286 said...

    Below are the correlations coefficients for final practice vs fast laps in the spring Bristol race.

    P3 single lap: -54025
    P3 10 Lap: -.61313

    *a negative coefficient means as practice rank decreases fast laps increase or vice versa.

    With those numbers it’d be hard for me NOT to consider practice speeds relevant. It will be interesting to see if the trend from single lap to 10 lap continues now that we can easily track 15, 20, 25, and 30 lap.

    This means you would identify the slow cars in practice and assume those same cars will be fastest in the race?

    May I ask how many races you sampled? If your sample size is small that may be problematic, as outliers will have too much influence on the coefficients.

    Also, did you use Pearson’s correlation coefficient or Spearman’s correlation coefficient? Spearman’s handles outliers better, but depending on the variance of the practice speeds it may not matter too much.

    Also, did you eliminate any drivers who did not participate in a P3, for whatever reason, from your sample?

    Did you adjust for race DNFs? A fast or slow car in practice that DNFs early in a race obviously no chance to accumulate a high number of fast laps if, using Bristol as an example, the driver crashes-out on lap 50 in a 500 lap race.

    ….

    Personally, I have serious concerns about relying too much on practice data/speed, at least for analytical purposes; whether it is high straight speed on a single lap; or 5, 10, 20, 30 lap averages.

    I will try to outline these concerns later in the forum.

  • gje627

    Per previous message, I’m going to run Spearman’s on final practice with fast laps. I will not use 10-lap numbers because I only have a couple of years of this data, therefore my results would not be statistically valid (wish I had 10 lap averages for all years). I’m using final practice numbers because since 2007, the second Bristol has always had only 2 practice sessions (the first race is always 3 practice sessions).

  • Toddalan2286

    @gje627 said...

    This means you would identify the slow cars in practice and assume those same cars will be fastest in the race?

    May I ask how many races you sampled? If your sample size is small that may be problematic, as outliers will have too much influence on the coefficients.

    Also, did you use Pearson’s correlation coefficient or Spearman’s correlation coefficient? Spearman’s handles outliers better, but depending on the variance of the practice speeds it may not matter too much.

    Also, did you eliminate any drivers who did not participate in a P3, for whatever reason, from your sample?

    Did you adjust for race DNFs? A fast or slow car in practice that DNFs early in a race obviously no chance to accumulate a high number of fast laps if, using Bristol as an example, the driver crashes-out on lap 50 in a 500 lap race.

    ….

    Personally, I have serious concerns about relying too much on practice data/speed, at least for analytical purposes; whether it is high straight speed on a single lap; or 5, 10, 20, 30 lap averages.

    I will try to outline these concerns later in the forum.

    My correlation was for 1 race, spring Bristol race as stated in my comments. I believe in doing this in a race by race basis and trend or look at each correlation separately because over time strategy, race script and other variables can muddy things up.

    If the driver did not post a rank they were excluded.

    I DO NOT remove or adjust for DNFs. If we are using practice as a predictive stat and we can’t predict crashes then I would consider removing those as data manipulation.

  • gje627

    @Toddalan2286 said...

    My correlation was for 1 race, spring Bristol race as stated in my comments. I believe in doing this in a race by race basis and trend or look at each correlation separately because over time strategy, race script and other variables can muddy things up.

    If the driver did not post a rank they were excluded.

    I DO NOT remove or adjust for DNFs. If we are using practice as a predictive stat and we can’t predict crashes then I would consider removing those as data manipulation.

    Okay, thanks. I’m afraid to say that your sample size is way, way too small.

    Also, I did run the numbers … I’ll post in a little bit.

    There is another huge problem, that makes any correlation between fast laps and any type of practice speed statistically invalid even with a large dataset. I’ll explain when I post my numbers.

  • Toddalan2286

    We will agree to disagree. You will run your correlation with more data points and probably get a result of somewhere between -.325 and -.450 give or take and that won’t tell us much. My correlation is stating for that particular race practice was a moderate indicator for fast laps.

    Saying practice doesn’t matter is misleading people. Practice gives us an idea of who can be competitive, it’s a data point we have given to us prior to the event. It may not predict exactly how many fast laps or where they finish but it’s important to use it in different ways. Below is a stat I’d personally like to keep but I’ll tell it to make my point.

    Since Texas 12 of the last 13 (might be 13 of the last 14) non restrictor plate races have had at least 1 driver ranking 1 or 2 in first practice in the optimal lineup, the one exception being the coke 600. Again practice gives us more data to look for patterns and to evaluate the field.

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Are you a DFS player who wants to get into sports betting?

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RotoGrinders.com is the home of the daily fantasy sports community. Our content, rankings, member blogs, promotions and forum discussion all cater to the players that like to create a new fantasy team every day of the week. Our goal is to help all of our members make more money playing daily fantasy sports!

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