{
  "id": 220002,
  "title": "Trust CV ? +0.001 score importance between CV and LB",
  "url": "/competitions/cassava-leaf-disease-classification/discussion/220002",
  "author_name": "",
  "post_date": "2021-02-17T05:55:12.411179700Z",
  "votes": 13,
  "comment_count": 3,
  "views": 0,
  "content": "<p>In this competition, we have about 21000 training images and 15000 test images. <br>\nPublic LB contains 31% test images (=4500 images).</p>\n<p>KFold CV score +0.001 means that additional 21 images are predicted correctly.<br>\nOn the other hand, LB +0.001 means that the increase of correct prediction is only 4 or 5, which is about 4~5 times smaller number than CV +0.001.</p>\n<p>Therefore, Trust CV is not bad strategy for selection of final submissions.<br>\nHow do you think about this?</p>",
  "messages": [
    {
      "id": "1206021",
      "postDate": "02/17/2021 05:55:12",
      "content": "<p>In this competition, we have about 21000 training images and 15000 test images. <br>\nPublic LB contains 31% test images (=4500 images).</p>\n<p>KFold CV score +0.001 means that additional 21 images are predicted correctly.<br>\nOn the other hand, LB +0.001 means that the increase of correct prediction is only 4 or 5, which is about 4~5 times smaller number than CV +0.001.</p>\n<p>Therefore, Trust CV is not bad strategy for selection of final submissions.<br>\nHow do you think about this?</p>",
      "rawMarkdown": "In this competition, we have about 21000 training images and 15000 test images. \nPublic LB contains 31% test images (=4500 images).\n\nKFold CV score +0.001 means that additional 21 images are predicted correctly.\nOn the other hand, LB +0.001 means that the increase of correct prediction is only 4 or 5, which is about 4~5 times smaller number than CV +0.001.\n\nTherefore, Trust CV is not bad strategy for selection of final submissions.\nHow do you think about this?",
      "votes": null
    },
    {
      "id": "1206040",
      "postDate": "02/17/2021 06:17:14",
      "content": "<p>well we had some leaks of private lb so this should be helpful <a href=\"https://www.kaggle.com/c/cassava-leaf-disease-classification/discussion/207410\" target=\"_blank\">https://www.kaggle.com/c/cassava-leaf-disease-classification/discussion/207410</a></p>",
      "rawMarkdown": "well we had some leaks of private lb so this should be helpful https://www.kaggle.com/c/cassava-leaf-disease-classification/discussion/207410",
      "votes": null
    },
    {
      "id": "1206500",
      "postDate": "02/17/2021 11:50:04",
      "content": "<p>The number of images in LB doesn't matter since it's very noisy. Even if it had had 100k images, I would have highly not recommend to you to estimate your models according the LB. A good CV strategy usually is much better way to estimate your models even if it has a much smaller number of images. The Stratified K-fold is a good example. 5 folds should be the best. I got some interesting results after switching from stratified train test split to stratified K-fold.</p>",
      "rawMarkdown": "The number of images in LB doesn't matter since it's very noisy. Even if it had had 100k images, I would have highly not recommend to you to estimate your models according the LB. A good CV strategy usually is much better way to estimate your models even if it has a much smaller number of images. The Stratified K-fold is a good example. 5 folds should be the best. I got some interesting results after switching from stratified train test split to stratified K-fold.",
      "votes": null
    },
    {
      "id": "1206749",
      "postDate": "02/17/2021 14:41:20",
      "content": "<p>Very good point, trusting lb is basicaly having a validation strategy with less images therefore less robust. Completely agree with you!</p>",
      "rawMarkdown": "Very good point, trusting lb is basicaly having a validation strategy with less images therefore less robust. Completely agree with you!",
      "votes": null
    }
  ],
  "comments": [
    {
      "id": 1206040,
      "author_name": "mithilsalunkhe",
      "author_url": "",
      "post_date": "02/17/2021 06:17:14",
      "content": "<p>well we had some leaks of private lb so this should be helpful <a href=\"https://www.kaggle.com/c/cassava-leaf-disease-classification/discussion/207410\" target=\"_blank\">https://www.kaggle.com/c/cassava-leaf-disease-classification/discussion/207410</a></p>",
      "votes": null,
      "replies": []
    },
    {
      "id": 1206500,
      "author_name": "vadimtimakin",
      "author_url": "",
      "post_date": "02/17/2021 11:50:04",
      "content": "<p>The number of images in LB doesn't matter since it's very noisy. Even if it had had 100k images, I would have highly not recommend to you to estimate your models according the LB. A good CV strategy usually is much better way to estimate your models even if it has a much smaller number of images. The Stratified K-fold is a good example. 5 folds should be the best. I got some interesting results after switching from stratified train test split to stratified K-fold.</p>",
      "votes": null,
      "replies": []
    },
    {
      "id": 1206749,
      "author_name": "yannmajewski",
      "author_url": "",
      "post_date": "02/17/2021 14:41:20",
      "content": "<p>Very good point, trusting lb is basicaly having a validation strategy with less images therefore less robust. Completely agree with you!</p>",
      "votes": null,
      "replies": []
    }
  ],
  "raw_markdown_by_id": {
    "1206021": "In this competition, we have about 21000 training images and 15000 test images. \nPublic LB contains 31% test images (=4500 images).\n\nKFold CV score +0.001 means that additional 21 images are predicted correctly.\nOn the other hand, LB +0.001 means that the increase of correct prediction is only 4 or 5, which is about 4~5 times smaller number than CV +0.001.\n\nTherefore, Trust CV is not bad strategy for selection of final submissions.\nHow do you think about this?",
    "1206040": "well we had some leaks of private lb so this should be helpful https://www.kaggle.com/c/cassava-leaf-disease-classification/discussion/207410",
    "1206500": "The number of images in LB doesn't matter since it's very noisy. Even if it had had 100k images, I would have highly not recommend to you to estimate your models according the LB. A good CV strategy usually is much better way to estimate your models even if it has a much smaller number of images. The Stratified K-fold is a good example. 5 folds should be the best. I got some interesting results after switching from stratified train test split to stratified K-fold.",
    "1206749": "Very good point, trusting lb is basicaly having a validation strategy with less images therefore less robust. Completely agree with you!"
  },
  "source": "meta"
}