2014年9月17日星期三

美國學術工作發佈時程

找美國學術工作,你會非常關注什麼時候工作會張貼出來,這樣你可以知道今年整體市場如何,決定要申請工作的數量。

那何時是美國學術工作張貼的高峰期呢?這問題很難說,而且每個領域是有些不同的。不過為了給大家一個概念,這裡採用了The Chronicle of Higher Education的文章,裡面轉用了Modern Language Association的資料。

下圖是2013年張貼出來英語文學的學術工作。從中你會看到,506個工作review在年底之前就開始,只有113個工作是到2014年才開始review的。換句話說,你如果要找明年八月開始的學術工作,今年開始申請,而且今年學校就會review你的申請材料了。

再具體一點。70%的工作是在12/1號之前開始評審。如果推算回去的話,趨勢一樣的情況下,那意思是大部分的美國學術工作,你可能已經可以在網路上找到資訊,或是在這一個星期左右就會看到。

就像下圖,十月有111個工作到deadline,那表示這些工作是更早以前張貼的,所以現在(九月到十月初)是找學術工作的重要期間,千萬不要錯過!但也有可能你的領域早一點或晚一點,這請詢問你的指導教授。

MLA job trend

上面的時間是說明在這段時間,有多少工作到了submission deadline。

2014年9月10日星期三

探索性因素分析模型契合方式的比較

前面的文章探索性因素分析的設計與使用 (一) 講到了模型契合方式的選擇裡面提到了幾種常用的方法:

常用的方法有 maximum likelihood (簡稱ML), pricipal factors with prior estimation of communalities, 和 iterative principal factors。

ML 的優點是可以得到較廣的模型適合度指標 (a wide rage of indexes of the goodness of fit of the model)。此外,ML 還允許測試 factor loadings 與因素之間的相關度是否為顯著。然而,ML 的限制是假設了多變量的常態性 (normality)。如果嚴重違反常態性,得出的結果將是扭曲的。

principal factor methods (包含 iterated 與 noniterated的。注意:principal factor methods 與主成份分析是不一樣的) 的優點則是沒有常態性分佈的假設。此外,principal factor methods 也較不會得到扭曲的結果。然而,此種方法的缺點是提供較少範圍的 goodness of fit indexes (適合度指標)。此外,一般來說也不提供 confidence intervals 和顯著測試。

 但這些解釋可能不是很直觀,所以找了個英文說明,讓大家更清楚。

 
  
 Factor analysis methods
來源:http://stats.stackexchange.com/questions/50745/best-factor-extraction-methods-with-reference-to-spss

探索性因素分析英文寫作

學統計的時候學的是觀念,但到了寫paper的時候,如何寫出來,還得在學學這些方面如何用英文來描述。另外,有時候分析都作了,但寫文章的時候又忘了,紀錄下這些步驟,也是提高文章的完整性。

下面針對探索性因素分析的部分,給出一些文章用的說法,大家自行修改,並附上一些寫作時可用的文獻。至於驗證性分析,目前還在整理,請大家靜待下一篇。

有些部分還不太全,這有空再補,或是請大家提供這方面有詳細描述的文章。文章也還有點亂,請大家包涵。如果有缺漏的地方,請大家指正。

探索性因素分析

可執行因素分析與否 (factorability)

這又叫作因子可分解性。
Evaluation of the correlation matrix indicated that it was factorable: Kaiser-Meyer-Olkin Measure of Sampling Adequacy = .##, which is “marvelous” (> .90) according to Kasier’s criteria (Pett, Lackey, & Sullivan, 2003).

The factorability of the matrix was determined using the Kaiser–Meyer–Olkin Measure of Sampling Adequacy (MSA). In our study, the MSAs for individual variables ranged from 0.89 to 0.97. The MSA for the entire matrix was 0.937. Each of these MSA values is well above the 0.80 meritorious level (Kaiser & Rice, 1974).

We examined the factorability through an inspection of the correlation matrix, and through conducting the Kaiser–Meyer–Olkin (KMO) measure of sampling adequacy and Bartlett’s test of sphericity. The KMO test yielded a measure of 0.815, and Coakes and Steed recommend that this measure should exceed 0.6 to proceed with factoring.
Bartlett’s test of sphericity was significant well beyond the 0.001 level.
參考文獻

Coakes, S. J., & Steed, L. G. (1997). SPSS analysis without anguish. Brisbane: John Wiley. (不建議引用)

Pett, M. A., Lackey, N. R., & Sullivan, J. J. (2003). Making sense of factor analysis: The use of factor analysis for instrument development in health care research. Thousand Oaks, CA: Sage Publications.
Kaiser, H. F., & Rice, J. (1974). Little Jiffy, Mark IV. Educational and Psychological Measurement, 34, 111–117.

探索性因素之間的關係

正交

A principal axis factor (PAF) analysis was carried out on the 28 items from the 問卷名 using 統計軟體.

Factor analysis was performed with SPSS #, employing a cut-off eigenvalue of 1 and VARIMAX rotation.
Each was a principal components analysis with varimax rotation.
A principal component factor analysis (PCFA) with Varimax rotation was used to determine the underlying structure of the data.

斜交

Oblique rotation methods allow for factors to be correlated, and the assumption was made that the 多少個 factors thought to be present in the 問卷 were related.

參考文獻
Preacher, K. J., & MacCallum, R. C. (2003). Repairing Tom Swift’s electric factor analysis machine. Understanding Statistics, 2, 13-43.

決定探索性因子的方法

The number of factors to extract was determined on the basis of several criteria, including parallel analysis, examination of the resulting scree plot, and eigen- values greater than 1.0 (i.e., the K1 criterion; Hayton, Allen, & Scarpello, 2004).

Eigenvalue

The K1 criterion suggested # initial factors.

# factors were identified using the latent root criterion, which is the most common technique for determining the number of factors to extract (Hair, Anderson, Tatham, & Black, 1998). The initial eigenvalues were greater than 1, which are considered significant.

Parallel analysis

The parallel analysis suggested that two factors should be retained.

Scree plot

Inspection of the scree plot, although subjective, seemed to suggest two or three factors.

參考文獻

Hair, J. E., Jr., Anderson, R. E., Tatham, R. L., & Black, W. C. (1998). Multivariate data analysis (5th ed.). Upper Saddle River, NJ: Prentice Hall.

Hayton, J. C., Allen, D. G., & Scarpello, V. (2004). Factor retention decisions in explor- atory factor analysis: A tutorial on parallel analysis. Organizational Research Methods, 7, 191-205.

Factor loadings

A cutoff for statistical significance of the factor loadings of 0.5 was used, because loadings of 0.5 or greater are also considered practically significant (Hair et al., 1998).

We adopted a factor loading criterion of 0.40 for inclusion of the item in the interpretation, more stringent than Tabachnik and Fidell (1996), who suggest 0.32, and consistent with Comrey and Lee (1992) who suggest that the criterion should be set a little higher than 0.32.

參考文獻
Comrey, A. L., & Lee, H. B. (1992). A first course in factor analysis (2nd ed.). Hillsdale, NJ: Erlbaum.


Hair, J. E., Jr., Anderson, R. E., Tatham, R. L., & Black, W. C. (1998). Multivariate data analysis (5th ed.). Upper Saddle River, NJ: Prentice Hall.

Pallant, J. (2001). SPSS survival manual. Crows Nest, NSW: Allen & Unwin. (不建議引用)

有因子load在兩個因素上

Where an item loaded on more than one factor, we have followed the advice of Arrindell et al. (1983) and have included the item in the factor on which it scored highest, provided the difference between the two-factor loadings was at least 0.2.

參考文獻

Arrindell, W. A., Emmelkamp, P. M. G., Brilman, E., & Monsma, A. (1983). Psychometric evaluation of an inventory for assessment of parental rearing practices. Acta Psychiatrica Scandinavica, 67, 163–177.

探索性因素分析的效度

Cronbach’s alpha

The Cronbach’s alpha for these ## items was .##.

The reliability of the questionnaire is satisfactory, with a Cronbach alpha of 0.83. Both Coakes and Steed (1997) and Pallant (2001) suggest that alpha values above 0.7 are sufficient for reliability to be assumed.

參考文獻

Coakes, S. J., & Steed, L. G. (1997). SPSS analysis without anguish. Brisbane: John Wiley. (不建議引用)

Comrey, A. L., & Lee, H. B. (1992). A first course in factor analysis (2nd ed.). Hillsdale, NJ:
Erlbaum.

Pallant, J. (2001). SPSS survival manual. Crows Nest, NSW: Allen & Unwin. (不建議引用)

Correlation matrix

Further inspection of the inter-item correlation matrix revealed some considerable redundancy in items A and B.Each of these items was highly correlated (r > .70) with four other items in the subscale. Therefore, these two items were deleted.

Further inspection of the inter-item correlation matrix revealed that item A had low correlations (r < .40) with # other items in the subscale.

範例文章

這些文章是我用關鍵字從我的文獻管理軟體找出來的,上面很多英語也是從下面的文章節出來的。大家可以參考一下。如果有更具有代表性的文章,歡迎在下面留言。


Artino, A., & McCoach, D. (2008). Development and initial validation of the online learning value and self-efficacy scale. Journal of Educational Computing Research, 38(3), 279-303. doi: 10.2190/EC.38.3.c

Muilenburg, L. Y., & Berge, Z. L. (2005). Student barriers to online learning: A factor analytic study. Distance Education, 26(1), 29-48. doi: 10.1080/01587910500081269

Smith, P. J., Murphy, K. L., & Mahoney, S. E. (2003). Towards identifying factors underlying readiness for online learning: An exploratory study. Distance Education, 24(1), 57-67. doi: 10.1080/01587910303043

Vallerand, R. J., Pelletier, L. G., Blais, M. R., Briere, N. M., Senecal, C., & Vallieres, E. F. (1992). The academic motivation scale: A measure of intrinsic, extrinsic, and amotivation in education. Educational and Psychological Measurement, 52(4), 1003-1017. doi: 10.1177/0013164492052004025

2014年9月1日星期一

美國歷史學博士就業狀況追蹤

在上一篇文章談美國教授薪水的時候,大家別顧著看薪水有多高。該份資料不分學科,所以你看到的薪水可能與你實際拿到的有很大的落差。不過關心薪水當然是好事,但更重要的是:你怎麼樣找到工作。如果你剛開始找美國的學術工作,可從找工作索引文章開始看起。

今天要講的就是美國歷史學博士的就業狀況。我本身不是學歷史的,寫這篇文章完全是因為美國歷史學會 (American Historical Association) 有一份非常詳細的資料,追蹤從1998-2009年之間,超過2500位歷史系的博士畢業生就業狀況。這裡面的結果非常有意思。

History phd placement

下面是主要發現:

1. 整體就業狀況良好:只有2位沒有就業。所以文科博士不一定代表比較難找工作

2. 50.6%在四年制大學任終身職軌道的教職 (tenure-track),2.4%在二年制大學任終身職軌道的教職 (見下圖)。

History phd placement 2

3. 從事美國歷史研究的,任終身職軌道教授的機會比從事非美國歷史研究的低25%,但從事美國歷史研究的比較有可能在非教授領域找到工作。

4. 如果在好的學校拿到Ph.D., 拿到終身職軌道教職的機會較高。—> 你的大學學歷與碩士學歷在哪拿的雖然也重要,但沒有博士在哪拿的重要。

5. 性別對於找到工作與否沒什麼影響。

6. 2/3 的博士畢業生在拿到Ph.D. 當地或在臨近區域找到工作,但在臨近區域工作的,比較不可能拿到tenure-track position。—> 要想找到終身職軌道教授,你除非是很厲害,要不然就是你得搬離你拿到博士的地方。

 

 

引用來源:http://www.historians.org/teaching-and-learning/current-projects/career-diversity-for-historians/the-many-careers-of-history-phds

American Historical Association

2014年8月20日星期三

美國教授薪水

求職季快到了,在美國想求職的同學,可以從之前的文章國際學生如何在美國找工作看起,另外,也可以看版上找工作的索引文章,相信會有不少幫助的。

在求職季到來的時候,很多人可能在想要繼續往學術界發展,或是往業界發展,甚至是自己出來創業。這個問題我沒辦法幫大家回答,但參考一下美國教授的薪水,你會比較有概念,並且知道如何取捨。

這是2013-14 AAUP Faculty Salary Survey的結果。

平均來說,Columbia University的full professors最高,年薪21萬5千5百美金。

2013 14 full professor salary

Associate Professors的話,哥倫比亞大學排名第一,在145,300。

2013 14 associate professor salary

Assistant Professors 的話,哥大約在11萬美金左右。

2013 14 assistant professor salary

看最高的薪水,其實不準確,因為美國各校差異大,各州的物價、生活水平相差非常多,所以你必須依照自己想去的地方、學校來作判斷。

一點資訊,僅供大家作參考。