{
  "synthetic": true,
  "execution": "Teaching record only; no live integration tested",
  "slug": "accessible-chart-data-contract",
  "group": "accessible-data",
  "title": [
    "Commission a chart with an inspectable data layer",
    "数据图交付，必须能查到图后的数"
  ],
  "intro": [
    "A business dashboard should let a reader recover the values, units and important pattern without relying on colour or a picture. Before commissioning a chart, approve its data table and a short interpretation. A decorative alt label cannot carry an entire quantitative comparison.",
    "企业仪表盘应让读者不靠颜色或图片，也能找到数值、单位及主要关系。委托画图前，先批准数据表和简短解释；装饰性的替代文字装不下完整数量比较。"
  ],
  "facts": [
    [
      "W3C WAI recommends short identification plus a detailed description for complex images, including relevant scales, values, relationships and trends.",
      "W3C WAI建议复杂图像同时提供简短识别及详细描述，覆盖相关尺度、数值、关系和趋势。",
      "https://www.w3.org/WAI/tutorials/images/complex/"
    ]
  ],
  "columns": [
    [
      "Synthetic month",
      "Order records / cancelled",
      "Net records in this example"
    ],
    [
      "合成月份",
      "订单记录／取消记录",
      "本例净记录"
    ]
  ],
  "example": [
    [
      [
        "July",
        "150 / 10",
        "140"
      ],
      [
        "七月",
        "150／10",
        "140"
      ]
    ],
    [
      [
        "August",
        "180 / 15",
        "165"
      ],
      [
        "八月",
        "180／15",
        "165"
      ]
    ],
    [
      [
        "September",
        "165 / 5",
        "160"
      ],
      [
        "九月",
        "165／5",
        "160"
      ]
    ],
    [
      [
        "Interpretation",
        "165−140=25;160−165=−5",
        "Increase then small decline; no revenue inference"
      ],
      [
        "解释",
        "165−140=25；160−165=−5",
        "先升后小幅下降，不能推算营收"
      ]
    ]
  ],
  "steps": [
    [
      "Define the grain, units, subtraction rule and period before drawing. In this teaching example a record is not a unique customer, a paid order or revenue.",
      "画图前定义粒度、单位、扣减口径和期间；本例记录不等于独立客户、已付款订单或营收。"
    ],
    [
      "Write a short label such as “Synthetic monthly order-record comparison” and provide the full table beside the chart or through a descriptive adjacent link. Keep the same values and ordering.",
      "简短标签可写“合成月度订单记录比较”，图旁直接放完整表格或描述性链接，数值与顺序一致。"
    ],
    [
      "Test whether a reader can answer highest month, largest change and exact value without viewing the graphic. Check keyboard access to the description and update both layers together.",
      "让读者不看图回答最高月份、最大变化及准确数值；检查键盘能否到达说明，并同步更新图和表。"
    ]
  ],
  "result": [
    "The maximum net value is 165 in August, and the three-month net total is 465. The description should state the rise from 140 to 165 and retreat to 160, rather than “business performance improved”. This is a complete teaching data layer a supplier can reproduce; it is not MadRaven trading data.",
    "最高净值是八月165，三个月合计465。说明应写140升到165再降到160，不能说“经营改善”。供应商可完整复现这层教学数据，但它不是MadRaven经营数据。"
  ],
  "accept": [
    "Require agreement between chart marks, accessible description, table and downloadable data after a value changes. Test meaning as well as the presence of an alt attribute.",
    "修改一个值后，图形、可访问说明、表格及下载数据必须一致；不仅检查有没有alt，还要检查意思。"
  ],
  "limit": [
    "Synthetic records only. No chart accessibility certification, live dashboard test or causal/business result is claimed. Interactive charts require additional keyboard and screen-reader testing.",
    "仅为合成记录，不声称无障碍认证、真实仪表盘实测或商业因果结果；交互图还须键盘及读屏测试。"
  ]
}