{
  "id": 1518,
  "title": "impression? what is it?anybody who can tell me,thx",
  "url": "/competitions/kddcup2012-track2/discussion/1518",
  "author_name": "",
  "post_date": "2012-03-11T13:54:21.857Z",
  "votes": null,
  "comment_count": 4,
  "views": 3485,
  "content": "<p>I do not clearly understand the description on &quot; impression &quot; in tha training dataset, but it seems to be a very important parameter for I saw this example given by authorities in the Evaluation part:</p>\r\n<p>&nbsp;<span style=\"font-size:large\"> &nbsp;if an instance has 40 impressions and 10 clicks, its empirical CTR is 10/40.</span></p>\r\n<p>Could anybody tell me what does &quot;impression&quot; mean？ Many thanks~~</p>",
  "messages": [
    {
      "id": "9223",
      "postDate": "03/11/2012 13:54:21",
      "content": "<p>I do not clearly understand the description on &quot; impression &quot; in tha training dataset, but it seems to be a very important parameter for I saw this example given by authorities in the Evaluation part:</p>\r\n<p>&nbsp;<span style=\"font-size:large\"> &nbsp;if an instance has 40 impressions and 10 clicks, its empirical CTR is 10/40.</span></p>\r\n<p>Could anybody tell me what does &quot;impression&quot; mean？ Many thanks~~</p>",
      "rawMarkdown": "",
      "votes": null
    },
    {
      "id": "9231",
      "postDate": "03/12/2012 02:08:40",
      "content": "<p>I think impression means the number of ads impressed in a session.</p>",
      "rawMarkdown": "",
      "votes": null
    },
    {
      "id": "9238",
      "postDate": "03/12/2012 12:21:32",
      "content": "<p>The number of times that a ad was shown to the user in a session</p>",
      "rawMarkdown": "",
      "votes": null
    },
    {
      "id": "9241",
      "postDate": "03/12/2012 13:16:11",
      "content": "<p>i don't think so, i think it means the number of sessions that the ad was shown to the user through he issue the same query</p>",
      "rawMarkdown": "",
      "votes": null
    },
    {
      "id": "9258",
      "postDate": "03/12/2012 21:17:51",
      "content": "<p>Well, it doesn't matter... <br>\r\nIt is only an aggregating field. Used to aggregate instances.<br>\r\nAn instance with 2 clicks and 9 impressions is the same as 9 instances with one impression each. 7 of them with 0 click, and two with 1 click (7 negative examples and 2 positive examples)</p>",
      "rawMarkdown": "",
      "votes": null
    }
  ],
  "comments": [
    {
      "id": 9231,
      "author_name": "sunsy1",
      "author_url": "",
      "post_date": "03/12/2012 02:08:40",
      "content": "<p>I think impression means the number of ads impressed in a session.</p>",
      "votes": null,
      "replies": []
    },
    {
      "id": 9238,
      "author_name": "leustagos",
      "author_url": "",
      "post_date": "03/12/2012 12:21:32",
      "content": "<p>The number of times that a ad was shown to the user in a session</p>",
      "votes": null,
      "replies": []
    },
    {
      "id": 9241,
      "author_name": "andyxs",
      "author_url": "",
      "post_date": "03/12/2012 13:16:11",
      "content": "<p>i don't think so, i think it means the number of sessions that the ad was shown to the user through he issue the same query</p>",
      "votes": null,
      "replies": []
    },
    {
      "id": 9258,
      "author_name": "leustagos",
      "author_url": "",
      "post_date": "03/12/2012 21:17:51",
      "content": "<p>Well, it doesn't matter... <br>\r\nIt is only an aggregating field. Used to aggregate instances.<br>\r\nAn instance with 2 clicks and 9 impressions is the same as 9 instances with one impression each. 7 of them with 0 click, and two with 1 click (7 negative examples and 2 positive examples)</p>",
      "votes": null,
      "replies": []
    }
  ],
  "raw_markdown_by_id": {
    "9223": "",
    "9231": "",
    "9238": "",
    "9241": "",
    "9258": ""
  },
  "source": "meta"
}