※ 引述《chenyutn (人生要死，何為苦心。)》之銘言： : 標題: Re: [問題] SEM用PLS跑的問題與優缺點? : 時間: Tue May 12 14:01:33 2009 : : : 推 chenyutn:bootstrap大約一千次就很足夠了 05/11 22:53 : : → chenyutn:畢竟現在電腦跑得很快啊 05/11 22:53 : : → danny789:老實說我有作過實驗resample設300-1000差異不大,並不是電 05/12 08:31 : : → danny789:腦速度的問題,而且在MIS領域我真沒看過設1000的paper 05/12 08:33 : : → danny789:所以resample並不是設越大越好,也必須有文獻支持吧? 05/12 08:34 : : 想說乾脆回文好了XD : : Preacher, K. J., & Hayes, A. F. (2008). Asymptotic and resampling strategies : for assessing and comparing indirect effects in multiple mediator models : : 這是其中的一段： : : There is no consensus as to how many bootstrap samples should : be generated, except that more is better. Given that the percentile end- : points are estimated using extremes of the sampling distribution and : that, for BCa intervals, a good estimate of the acceleration constant : is needed, it is important to minimize sampling variance in these es- : timates. We recommend at least 5,000 resamples for final reporting, : although 1,000 is probably sufficient for preliminary analyses. There : is little reason to use fewer, given the speed of today’s desktop comput- : ing technology. : : 這段也是我的立論基礎，雖然在數字設定多少才算大方面仍沒有立論，但resample : 的確是設越大越好。 : : 我想，這應該不會因傳播或MIS領域不同而變吧？ : : 還是說，有別的研究者有不同意見的？由於我是傳播領域的，所以看的多半是傳播 : 類的paper，但這幾篇都有討論到resample數，不知道其他領域（例如統計）的paper : 是不是也有討論到，而有不同意見？ 關於 resample 是不是設越大越好? 其實我找不到文獻支持, 所以我也不敢評論. 並且 Behavior Research Methods 是否是該領域不錯的 Journal 我也不懂 不過我用 ABI/INFORM Global 及 ScienceDirect (SDOL/SDOS) 都查無此 Journal title 不知何因 ? 還有此篇右下角有學術期刊所沒有的 "Copyright 2008 Psychonomic Society, Inc." 不知道這是指什麼? 關於這篇文獻(Preacher, 2008)的網路 pdf, 我初略的看了一下內容 我對此篇探討 PLS 而沒有提到 chin 感到有點疑惑, 當然也不是一定要引用 chin 只是有點怪 不知道是否有其他比較強(多)的證據或文獻可以證明 resample size 設越大越好? 以下引用 chin(2001)的 PLS-Graph User's Guide 內容片段 (已有 MIS 領域不錯的 Journal paper 引用) The default Bootstrap options are 100 resamples with each sample consisting of the same number of cases as your original sample set. The bootstrap procedure samples with replacement from your original sample set. It continues to sample until it reaches the number of cases you specify (or the default). This procedure is repeated until it reaches the number of bootstrap resamples you specify (or the default of 100). In general, resamples of 200 tend to provide reasonable standard error estimates. 以下是快速找到的幾篇 MIS papers Resample = 100 Henry, R.M., McCray, G.E., Purvis, R.L. Roberts, T.L. (2007) "Exploiting Organizational Knowledge in Developing IS Project Cost and Schedule Estimates: An Empirical Study", Information & Management, Vol. 44 No.6, pp.598-612. Resample = 500 Ko, D., Kirsch, J.L., King, W.R. (2005) "Antecedents of knowledge transfer from consultants to clients in enterprise system implementations", MIS Quarterly, Vol. 29 No.1, pp.59-85. Resample = 100 & 500 Goodhue, D., Lewis, W., and Thompson, R., (2007) "Statistical Power in Analyzing Interaction Effects: Questioning the Advantage of PLS With Product Indicators", Information Systems Research, Vol. 18 No.2, pp.211-227. 也許 Goodhue et al.(2007) 這篇是答案, 但我找不到 pdf 檔可以看(汗) ※ 編輯: danny789 來自: 122.254.33.185 (05/12 23:00)