Monday, November 24, 2008

Image File Formats

When you are working in a program such as PowerPoint and decide that you wish to insert an image into one of your slides, often you do not consider the file format in which the image has been saved. However, there are a number of different formats in which the files might have been saved, and this entry will provide a brief introduction to each. Information presented here is from the wonderful book “How to Wow with PowerPoint.” (1)

Windows Metafile: This is a proprietary format designed by Microsoft which can be used across all their platforms: Word, Excel, PowerPoint Access, FrontPage, etc. You will see such images saved as either .wmf files (16-bit information) or .emf files (enhanced metafiles, 32-bit information). Bit here refers to the amount of gray the image supports. In the case of 16-bit, that really means 2 raised to the 16th power; and for 32-bit, 2 raised to the 32nd power.

Windows Bitmap: This is generally used across Windows, and is compatible with most applications used by Windows-based computers. The problem with this format (which will be saved as .bmp, .dib, or .rle files) is that it is not compressed, meaning that if you insert such an image into, say, PowerPoint it will cause a delay in loading, projecting or advancing a slide. For large images, it is better to use a compressed format (such as a JPEG).

Computer Graphics Metafile: CGM files are used more in technical fields such as engineering, and in the military, but is not commonly used on the internet.

Graphics Interchange Format: Known as .gif files, this was originally designed for use by CompuServe, but remains in common use. Its files are limited to 256 colors, which makes their use for reproducing photographs problematic; you are exchanging file size for clarity. GIFs are typically used for embedded transparency or basic animations.

Joint Photographic Experts Group: These are known as JPEGs, and are used predominantly for formatting large photos for use in multimedia presentations, such as a slide show. This is best suited for images with many colors, but one should know that the manner in which it is processed allows data contained in the image to eliminated or deleted, so that as it is re-used it will begin to degrade.

Portable Network Graphics: This is a format that attempts to combine the best elements of JPEGs and GIF files. It has a 24-bit image and also will allow for transparency of images (which people often use to place a logo on a master slide).Older web browsers will not support this, but it is effective in presentation technology. Files are saved as .png.

Macintosh PICT: Before Mac had its OS-X (in all its large cat versions), this was the original graphic element, saved as .pct. It is becoming less common now, but may be seen when working with older programs that have embedded graphics.

Tagged Image File Format: This is the .tif file. This is used for high-quality printing projects, though such files, because of their high image quality, typically are very large. Fortunately, they can be compressed in order to reduce file size.

Vector Markup Language: This is a relatively new language that is being advanced by Microsoft and by the W3C, which is the group who sets standards for the Web. All .vml files are supported by the newest web browsers and are based on an XML exchange (a means to share information across many platforms).

This is just an overview of something we rarely think about, but which can affect the effectiveness of our multimedia presentations. There are means within programs such as PowerPoint to convert one file format into others, if ever problems exist in projecting a graphic. The Clip Organizer can do when necessary.

Please, everyone, have a wonderful Thanksgiving break.


1. Harrington R, Reckdall S. How to Wow with PowerPoint. Berkeley, CA; Peachpit Press, 2007

Monday, November 17, 2008

Excel PivotPoint Tables

This past week I attended a webinar program that demonstrated the use of Excel PivotPoint tables for analyzing information in large spreadsheet documents. As I sat through the program, I remember reaching a point where I said to myself, wow, this is really cool! And after the program ended and I had a chance to process the information while talking to some of my colleagues, they also expressed much the same sentiment about the usefulness of this component of the Excel program. I thought I would use this blog entry to simply describe what it does.

A Pivot Table is an excellent means to analyze data that is contained in a list. For example, imagine that you have a spreadsheet that contains the following information: Clothing Type (dresses, belts, pants, ties, shirts), Region (pacific, mountain, south, midwest, northeast), Sales (listed in dollars), Quarter (1,2,3,4) and Sales Type (Retail, Wholesale). And now imagine that you want to extract information from this table, which we will say contains 2400 entries. Say, you wish to look at the breakdown of wholesale versus retail sales, for each clothing type, broken down by region of the country. How can you easily do so? Well, a simple filter will not work, not with 2400 entries and with several different variables to consider. And even if you could, it would require a number of steps to get to the information, which would still be in columnar form and would require additional steps to provide the financial data. So, in a situation like this, a Pivot Table works perfectly, and has the added benefit of being able to be constructed in minutes. Not only that, but it is a simple matter to manipulate the data, which is why it is called a Pivot Table; one can pivot the axes in just two simple clicks of the mouse. Even better, a Pivot Table is something separate from the original data, so you can alter the table without affecting your original data source. It is in fact dependent on that original data.

There are a couple of prerequisites to set up a Pivot Table. You need to have a single title row across the top of your spreadsheet, with unique field headings. For the example I used just above, the headings would be as noted: Clothing Type, Region, Sales, Quarter, and Sales Type. And there can be no breaks in the data, i.e., you cannot have a missing line at line 1400, so no empty columns or rows. To make a table all you need to is make sure you have clicked on any cell within the spreadsheet; then, go to the Data menu at the top of the menu bar. Click on that, and use the pull down menu to go to the entry for “Pivot table and Pivot Chart Report…” This will open a dialogue box called the Pivot Table and Pivot Chart Wizard. Assuming you are working solely with Excel data, select the data you wish to analyze (here, it will be “Microsoft Office Excel list or database”) and then click “Next.” It will then ask you where the data is you wish to assess, and by default will enter the full spreadsheet range. Click “Next” again. It will then ask where you want to put the Pivot Table report. You can enter it either on the sheet you are working from, or have it open on its own sheet. Pick whichever you wish.

Once you do, you will be provided with a blank Pivot Table and a floating Pivot Table Field List (you use this for developing the table). From here, all you need to do is drag and drop. If you look at the blank table, you will see it has several components: on the left is a part that says “Drop Row Fields Here”, across the top is one saying “Drop Column Fields Here”; above that is one saying “Drop Page Fields Here,” and finally is the main box, which says “Drop Data Items here.” You would go to the floating box and simply drag the items you wish to analyze to the appropriate location- which depends on what you wish to analyze. For example, you could drag “Clothing Type” to the “Drop Row Fields Here” location and also drag “Region” to the “Drop Column Fields Here” location. As soon as you do, you would find that the table would tell you how many of each clothing type sold in each region of the country. And all done in seconds. And such tables can be made more complex by additional dropping; we could actually divide the clothing sales type into retail and wholesale with one simple additional drag and drop.

It is actually best to see this demonstrated. This link, to a website at Duke University, provides a very nice demonstration of how what I describe above is done.

The beauty of this tool is the ease it offers for doing detailed data analysis. It is up to the creativity of the user to find the best ways in which this can be used in educational settings.

Monday, November 10, 2008

The SPICES Model: S. Systematic vs. Apprenticeship or Opportunistic Program

In our final entry on Harden’s SPICES model (1), the S distinguishes between a planned, systematic clinical experience versus one that is built around apprenticeship where trainees are “bonded” to their master and acquire skills by following him around and working with him. Examples of this latter approach can be found in our culture through the model of, say, a Jedi knight undergoing training as a “padawan” (novice) following a Jedi master, or by those doctors lucky (or unlucky) enough to work for Gregory House on House, MD. In truth, this problems affects medical education is some ways far more than it can chiropractic education, because we do not have the breadth of hospital contacts that medical students may be involved with, but our preceptor model is built on the idea of an apprenticeship model, though for reasons we can well understand.

In the apprenticeship model, students are assigned to a single teacher, or to a clinical unit or ward, for some period of time. They work on that ward, seeing only those patients on the ward, and therefore see only those conditions that opportunistically present themselves in the unit or clinic. What this means is that these patients are not predicted, nor predictable, which might seem obvious on first thought, but which has implications for planning and training. We would not normally build classes on content that we could not predict, for example. So what students learn, what they are exposed to, is built around which patients are available, the interests of clinic doctors with whom they work, and some change. Students may never get exposure to a representative sample of chiropractic or medical practice. This is less so in chiropractic, since our patient base is typically looking for relief of back pain, but still holds true in general.

The latest thinking is that it would be better if we did not leave clinical training to chance. This requires us to look at clinical training in a new way, one that is systematic and which is designed for all students so that they all get experiences that are necessary for their training. Thus, it may require students rotating through specialties and in various kinds of settings. This still requires enough planning that students understand the expectations and are given a list of skills that need to master, as well as a list of conditions that they are expected to see. Such an approach could be adapted within our own educational settings.

Harden suggests the following factors support a move to a more systematic approach: (1) Students need to experience a range and variety of health problems. Our own research shows that most of our students are exposed to musculoskeletal problems, but not to organic disease, for example, as they do their internships in our clinics. (2) It can help rationalize competencies, letting us know which are essential and which are useful but not absolutely necessary. All chiropractic interns should see cases of shoulder pain, but they do not all need to see cases of food allergy, for example. (3) It allows for better use of time. Once we have seen certain conditions, we may not need to spend much more time seeing many more cases, in the limited training time we have. We could move on.

The benefits of an apprentice ship model include (1) It has organizational advantages. This is a far easier approach to administrate. (2) There is continuity of teaching. A good relationship with a teacher always helps enhance learning.

This completes our discussion of Harden’s model, which can be used in how you plan your curriculum, and in how you see yourself positioning your class along the spectrum that exists for all six components of the model. There is no one perfect position for each decision level; it simply requires you to consider what it is you are trying to do. I hope that it will be of help to you.


1. Harden RM, Sowden S, Dunn WR. ASME Medical Education Booklet No. 18. The SPICES Model. Med Educ 1984;18:284-297

Tuesday, November 4, 2008

The SPICES Model: E. Electives vs. Standard Programs

In Harden’s SPICES model (1), the E defines distinctions between elective programs and a standard course of study. In a standard program, all the students pass through a prescribed set of course, and have few opportunities to study a subject of their own choosing that is outside those courses set in the program. This is very much what the case was when I was a student at National College of Chiropractic; there was a prescribed set of courses and only a single elective course, acupuncture (and that because many states did not allow the practice of acupuncture by chiropractic physicians).

Elective programs that students can choose from allow a student to follow his or her own muse. Such programs can occur in a number of ways: as a single stand-alone class in a given term, as an independent study course, or as a series over time. At Palmer College, students can take elective classes in a variety of chiropractic techniques, for example. In the clinical research master’s program, students can take electives in biomechanics, and they can also design their own independent study course. Such courses have, in the past, included low back outcome assessment instruments, neurophysiology, pediatric journal assessment, etc. The point is that in each case a student designed a course that allowed him or her to pursue a personal interest. And in US medical education, there are even a few programs, such as Stanford University, where the entire curriculum is elective-based, where students can choose their own basic and clinical science courses.

Electives have many benefits. Harden notes that they are a way of coping with an over-crowded curriculum. This arises because as knowledge expands, it is not possible to cover everything, and in curriculum planning using electives may be a way to help students tackle areas where they feel they have interest, or deficiency. Electives provide a means for students to take more responsibility for their own learning. Further, electives can help facilitate career choice by students, and they can help students meet their own personal aspirations. Elective courses can lead to attitude changes as well.

But there are benefits to the standard program as well. Electives require more teachers and more teaching time, and we are all already quite busy. Not all faculty may be interested in teaching such courses. But the presence of electives can have beneficial effects on the standard courses. Program assessment in a standard program is pretty well understood, but it is harder to assess electives.

A combination of electives and a standard program may help make the educational experience in chiropractic more personalized and therefore more personally meaningful. All chiropractic programs have adopted some manner of offering elective courses.


1. Harden RM, Sowden S, Dunn WR. ASME Medical Education Booklet No. 18. The SPICES Model. Med Educ 1984;18:284-297