【正文】 Analysis (MSA) Attribute Purpose Of Attribute MSA ? Accuracy checks 準(zhǔn)確性檢查 Assess standards against customers’ requirements 評(píng)價(jià)標(biāo)準(zhǔn)和顧客要求對(duì)比 Identify how well Measurement System conforms to a “known master” /識(shí)別測(cè)量系統(tǒng)符合 ”已知標(biāo)準(zhǔn) ”的程度 ? Precision checks 精密性檢查 To determine if inspectors (Appraisers) across all shifts, machines, lines, etc… use the same criteria to evaluate items – Reproducibility / 確認(rèn)檢查員 (評(píng)價(jià)者 )所有班次、設(shè)備、生產(chǎn)線是否使用相同標(biāo)準(zhǔn)評(píng)價(jià) – 再現(xiàn)性 To quantify the ability of inspectors (Appraisers) or gages to accurately repeat their inspection decisions – Repeatability / 量化檢查員 (評(píng)價(jià)者 )或儀器準(zhǔn)確重復(fù)檢查結(jié)果的能力 –重復(fù)性 ? To identify how well inspectors/gages measure a known master (possibly defined by the customer) to ensure no misclassification occurs /識(shí)別檢查員 /儀器測(cè)量 ”已知標(biāo)準(zhǔn) ”(可能是顧客定義 )確保沒有錯(cuò)誤分類的能力 How often operators decide to ship truly defective product 多久操作員會(huì)將不良品判為合格品？ How often operators do not ship truly acceptable product 多久操作員會(huì)將合格品判為不良品？ ? To determine areas where 確定以下范圍 Training is needed 是否需要培訓(xùn) Procedures or Control Plans are lacking 是否缺乏程序或控制計(jì)劃 Standards are not clearly defined 標(biāo)準(zhǔn)是否未定義 Gage adjustment or correlation is necessary 儀器調(diào)整或相互性是必須的 4 Measurement Systems Analysis (MSA) Attribute Attribute Data With Unordered Categories非順序型的屬性數(shù)據(jù) – Kappa ? Suppose that invoice quality is a key to the process Throughput. In other words, if an invoice is inplete, the rework required impacts the quantity that can be processed in a day. Two Appraisers are asked to independently evaluate ten invoices randomly selected from different days. The results of the study are shown below:/假定發(fā)票質(zhì)量是過程輸出的關(guān)鍵，換句話說，如果一張發(fā)票不完整，再作業(yè)就會(huì)影響當(dāng)天的產(chǎn)量。結(jié)果如下所示： Invoice Appraiser 1 Appraiser 2 Agreement? 1 Bad Bad Y 2 Good Bad N 3 Good Good Y 4 Bad Bad Y 5 Good Good Y 6 Good Good Y 7 Good Bad N 8 Good Bad N 9 Good Good Y 10 Good Good Y ? We could simply look at the percent of the time they agree as metric for between Appraiser agreement: 我們可以只考慮評(píng)價(jià)者判定一致的百分率作為衡量指標(biāo) ? But what would that not take into account? 但是還有什么沒有考慮？ _____ % agree _____ % disagree 5 Measurement Systems Analysis (MSA) Attribute Kappa pares the proportion of agreement between Appraisers after removing agreement by chance / Kappa 比較了評(píng)價(jià)者之間去除了的偶然性的一致性比率 The proportion that the judges are in agreement is Pobserved /判斷一致的比率是 Pobserved The proportion expected to occur by chance is: 由于偶然性一致的比率 Pchance = (P Insp1 Good) (P Insp2 Good) + (P Insp1 Bad)(PInsp2 Bad) 1. What would the Kappa be if the judges agreed on every part?/如果每個(gè) 零件的判定都一致， Kappa是多少？ 2. How would you interpret a Kappa of zero?怎么解釋 Kappa為 0？ 3. What would be the Kappa if the judges never agreed? 如果判定都不一 致 Kappa又是多少？ Definition Of Kappa cha ncecha nceobs erv e dP1 PPKap pa ? ??Let’s walk through the calculation by hand. 6 Measurement Systems Analysis (MSA) Attribute How To Calculate Kappa – By Hand Build contingency table Sum columns and rows Calculate Pobs by adding diagonal Calculate Pchance Calculate Kappa Pchance = (PR1bad)(PR2bad)+(PR1good)(PR2good) = (.2)(.5)+(.8)(.5) = .5 Pobs Pchance Kappa = 1 Pchance =(.)/() = .2 .8 .5 .5 Bad Good Appraiser 1 Good Bad Appraiser 2 Pobs = .5 + .2 = .7 3/10 = .3 2/10 = .2 0/10 = 0 5/10 = .5 Add Add Add Add How is this interpreted? 7 Measurement Systems Analysis (MSA) Attribute How To Interpret Kappa Results The general rule for interpreting Kappa results are as follows: 解釋Kappa的規(guī)則通常如下 ? 0 – Nonrandom disagreement 非隨機(jī)的不一致 ? – Measurement System needs attention 測(cè)量系統(tǒng)需關(guān)注 ? – Generally acceptable, improvement may be needed depending on application and risk 通?？山邮埽鶕?jù)需要和 風(fēng)險(xiǎn)進(jìn)行改善 ? – Excellent Measurement System 極好的測(cè)量系統(tǒng) Remember, consider your Measurement System and how well the above criteria might apply. 8 Measurement Systems Analysis (MSA) Attribute Attribute Data – Kappa Exercise 1. Your pany produces documents that are filled with alphanumeric characters. If a document has one or more numerals (09), it is defective. Your mission is to identify the defective documents./你公司的產(chǎn)品是字母與數(shù)字混合編排的文件。你的任務(wù)就是識(shí)別不合格的文件。練習(xí)在 60s內(nèi)完成 (3s/部件 ). 4. Each Appraiser will perform two trials 每個(gè)評(píng)價(jià)者重復(fù) 2次 5. Perform analysis in MINITAB174。 assessments agree with each other. Kappa Statistics Response Kappa SE Kappa Z P(vs. 0) b g MINITAB Output – Session Window Since Kappa for both Appraisers, both agree well with themselves/ 2個(gè)評(píng)價(jià)者 Kappa ，一致度較好 ? Adequate repeatability/足夠的重復(fù)性 Since Kappa for the Between Appraisers,/ 評(píng)價(jià)者間的 Kappa ? Adequate reproducibility/足夠的再現(xiàn)性 13 Measureme