Category Archives: Uncategorized

Restricted cubic splines in regression

Earlier this year, Angela O’Brien-Malone and I were working on some research that involved quantile regression using restricted cubic splines. Almost without exception, the papers that I read on cubic splines cited a paper by Stone and Koo published in 1985 in the Statistical Computing Section of the Proceedings of the American Statistical Association. Clearly, the authors of the papers that I read had better library resources than I, or perhaps they did not actually read the original paper and merely cited secondary sources! Despite contacting several libraries, I found myself completely unable to obtain a copy of the paper.

Eventually I had the idea of looking to see whether I could contact the authors and by good fortune found the email address for Charles J. Stone, Professor Emeritus of Statistics at the University of California (Berkley). By even greater fortune, Professor Stone had a copy of the paper which he kindly scanned and emailed to me. Now I, like many other readers of mathematics, like to see it beautifully typeset but in 1985 when Stone and Koo’s paper was originally published, the Statistical Computing Section of the ASA was using fonts that did the mathematics little justice. So, with Professor Stone’s permission, and as a way of saying “thank you”, I have reprintted the paper using LaTex. The images are taken directly from a scanned copy of the original.

Two versions of the paper are available for download here: For North American readers, there is a copy fitted to letter-size paper. For others, there is an A4 sized copy. The paper should be cited as:
Stone, C. J., & Koo, C.-Y. (Cha-Yong) (1985). Additive splines in statistics. Proceedings of the Statistical Computing Section, American Statistical Association 27, 45-48.

I should add that I have been very remiss in taking so long to make the paper available. I shall post an excuse at a later date …

Import into iTunes simultaneously from two CD drives

If you have more than one CD or DVD drive available on your computer then you might want to use both simultaneously to import CDs into Apple iTunes. There are a number of comments posted some years back indicating that it is not possible to import two CDs simultaneously and that it is only possible to organize for the CDs to be imported sequentially.

That might have been the case but with iTunes version 12.0.1.26 for Windows 7, it is possible to import simultaneously from two CDs but it requires a little non-intuitive trick. Here’s how. First ensure that your preferences indicate that you do not want CDs to be automatically imported! Second, load one CD, allow iTunes to identify the CD on the Gracenote database (if that is how your preferences have been set) and then, when you are asked, indicate that you want to import the CD. Thirdly, insert your second CD into your other CD or DVD drive, identify the CD if necessary, and then, when asked, indicate (counterintuitively!) that you do not want to import the (second) CD. Then, directly contrary to the question you have just answered, click the “Import CD” at the top of the window to indicate that you do want to import the CD after all. Now you should find that both CDs are being read into iTunes simultaneously and not merely put sequentially into a request queue.

Now for the things that can go wrong! If you make the mistake of answering “Yes” to the question “Do you wish to import the CD?” then you will find that the CDs are not imported simultaneouly and that you must wait for the importation of the first CD to finish before iTunes commences on the second disc. Further, if you answer “Yes” even once, then it messes things up for the remainder of that iTunes session. For example, if you are in the process of copying one disc, then insert the second and say “Yes” to the importation question, then (a) you will find that the importation is delayed, and (2) clicking on “Stop CD import” and then clicking on “Import CD” will not save the day. Not only will the importation of the second disc be delayed but even when both the importation of both discs is complete and you want to import another two, you will find that the error you made earlier prevents the simultaneous importation of any further discs. You will have to exit from iTunes, restart, and do things correctly.

I have used this method many times without a hitch; moreover, the two discs get imported in just about the same time as a single dics would normally take, without any noticeable reduction in the speed that one obtains when the discs are imported separately.

Search www.startpage.com from the address bar

If you type words into the address bar of Mozilla Firefox, and the words do not look like a valid URL, then the words will be passed to the default search engine (Google in the case of Firefox) as search terms. For example, a string such as ‘whodat.dere’ will be parsed as a domain name to be resolved, but ‘whodat dere’ or just ‘whodat’ will be passed to the search engine.

I generally use the privacy-respecting search engine at www.startpage.com. How can that be made the default search engine so that words accidentally typed into the address bar do not get sent to Google? Easy! In the address bar, enter about:config and confirm that you understand what you are doing. Search for the preference name (i.e., the entry) called keyword.URL. Double-click on the preference name. When Firefox asks you to enter a string, type https://www.startpage.com/do/search?query= and then click OK. It also makes sense to change the entry called browser.search.defaultenginename to Startpage but, so far as I can tell, that is a purely cosmetic change.

The default search engine can be set to anything else you want. For example:

Yahoo: http://search.yahoo.com/search?p=

Ask: http://www.ask.com/web?q=

Bing: http://www.bing.com/search?ie=UTF-8&oe=UTF-8&sourceid=navclient&gfns=1&q=

Google: http://www.google.com/search?&q=

Scoring the Values in Action Inventory of Strengths for Youth (VIA-Youth)

The Values in Action Inventory for Youth (VIA-Youth) is a 198 item self-report questionnaire that is very similar to the better known VIA Survey of Character. It was developed by Nansoon Park and Christopher Peterson who first described it, I think, in a paper [3] in the Journal of Adolescence. The VIA-Youth measures 24 so-called ‘character strengths’ [4] organized under six broad ‘virtues’ and is intended for use with young people aged 10–17 years.

The journal paper [3] explains that the authors, &#8216experimented with different item formats and phrasings before arriving at the current inventory, which contains 198 items (7–9 items for each of the 24 strengths, placed in a nonsystematic order), about one-third of which are reverse-scored. … Respondents use a 5-point scale to indicate whether the item is “very much like me” (=5) or “not like me at all” (=1). Subscale scores are formed by averaging the relevant items.’ Unfortunately the explanation of the scoring ends there.

I had not heard of the VIA-Youth until yesterday when I was asked, by someone who had seen my earlier blog posting [2] on the VIA Survey of Character, whether I knew anything about the VIA-Youth scale. I didn’t, but found, amongst other copies, a Master of Science dissertation [1] that contains a copy of the VIA-Youth. With a knowledge of the 24 character strengths, it is not difficult to infer the scoring key.

There are some differences from the way that the adult scale is scored. Items 1–168 are in seven repeating blocks of 24 questions. Within the 24 item blocks, the Character Strengths are in the same order. However, the items from 169–198 are different. The next block would normally be from 169–192, but in fact it is from 169–191 because the item for the character-strength of “Forgiveness” has been omitted. The remaining 7 questions (192–198) are for the character strengths called Fairness, Humour, Perseverance, Kindness, Love, Humility and Self Regulation.

The other difference between the Youth scale and the adult scale is that all the adult items are scored the same way. However, as Park and Peterson commented in their paper, some of the youth items are scored in the reverse direction. I have provided links to two spreadsheets that describe the scoring key completely. The first spreadsheet is in Open Document format [ODS-link], the other in Microsoft Excel format [XLS-link]. I have indicated in the spreadsheet whether the item is scored in the + direction or the – direction. More clearly, I have indicated whether the responses should be scored 5..1 (meaning that “Very Much Like Me” is 5, and “Not Like Me At all” is 1), or 1..5 (meaning that “Very Much Like Me” is 1, and “Not Like Me At all” is 5).

I expect that having the scoring key readily available will promote greater empirical examination of the scale.

References

[1] Dieckman, D. (2009). Locker Room To Life: Do Sports Build Character? Dissertation for the degree of Master of Science in Guidance and Counseling. University of Wisconsin-Stout. [link]

[2] Diamond, M., O’Brien-Malone, A., & Woodworth, R. J. (2010). Scoring the VIA Survey of Character. Psychological Reports, 107(4), 833-836. DOI: 10.2466/02.07.09.PR0.107.6.833-836

[3] Park, N., & Peterson, C. (2006). Moral competence and character strengths among adolescents: The development and validation of the Values in Action Inventory of Strengths for Youth. Journal of Adolescence, 29(6), 891–909. DOI: 10.1016/j.adolescence.2006.04.011

[4] Petersen, C., & Seligman, M. (2004). Character Strengths and Virtues: A Handbook and Classification. Oxford: Oxford University Press.

Targeting Skills Needs in Regions

Tools of trade

Targeting Skills Needs in Regions was the name given by the Australian Government to a program that was intended to alleviate a critical shortage of skilled labour in some regions of Australia.

A report on the evaluation of the program was recently published by the Australian Government Department of Education, Employment and Workplace Relations. A copy of the report can be downloaded from here. The copy was obtained from http://www.deewr.gov.au/Skills/Resources/Publications/Pages/RegionalSkills.aspx on 21 December 2011 at 02:31 hrs.