Tag Archives: education

Improve Writing Quality with Speaking & Storyboarding

For a decade, I supervised undergrads and grad students as they were completing writing projects: term papers, semester projects, and of course — capstone projects and thesis work. Today, I’m responsible for editing the work of (and mentoring) junior colleagues. The main lesson I’ve learned over this time is: writing is really hard for most people. So I’m here to help you.

If I had a dollar for every time this scenario happened, I’d… well, you get my point:

ME (reading their “final draft”): [Voice in Head] Huh? Wow, that sentence is long. OK, start it again. I don’t understand what they’re saying. What are they trying to say? This doesn’t make any sense. It could mean… no, that’s not it. Maybe they mean… nope, that can’t be it.

ME: So this sentence here, the one that says “Start by commutating and telling the story of what the purpose of the company’s quality management software is, the implementation plans and the impact to the current state of quality roles and responsibilities for everyone involved.”

THEM (laughing): Oh! Commutating isn’t a word. I meant communicating.

ME: Have you tried reading this sentence out loud?

THEM (still laughing, trying to read it): Yeah, that doesn’t really make sense.

ME: What were you trying to say?

THEM: I was trying to say “Start by explaining how quality management software will impact everyone’s roles and responsibilities.”

ME: Well, why don’t you say that?

THEM: You mean I can just say that? Don’t I need to make it sound good?

ME: You did just make it sound good when you said what you were trying to say.

By trying to “make it sound good” — it’s more likely that you’ll mess it up. People think speaking and writing are two different practices, but when you write, it’s really important that when you speak it out loud, it sounds like you’re a human talking to another human. If you wouldn’t say what you wrote to someone in your target audience in exactly the way that you wrote it, then you need to revise it to something you would say.

Why? Because people read text using the voice in their heads. It’s a speaking voice! So give it good, easy, flowing sentences to speak to itself with.

There are two ways you can start improving your writing today:

  1. Read your writing out loud (preferably to someone else who’s not familiar with your topic, or a collaborator). If it doesn’t sound right, it’s not right.
  2. Use a storyboard. (What does that mean?)

There are many storyboard templates available online, but the storyboard attached to this post is geared towards developing the skills needed for technical writing. (That is, writing where it’s important to support your statements with citations that can be validated.) Not only does citing sources add credibility, but it also gives your reader more material to read if they want to go deeper.

The process is simple: start by outlining your main message. That means:

  1. Figure out meaningful section headers that are meaningful on their own.
  2. Within each section, write a complete phrase or sentence to describe the main point of each paragraph or small group of paragraphs
  3. For each phrase or sentence that forms your story, cut and paste material from your references that supports your point, and list the citation (I prefer APA style) so you don’t forget it.
  4. Read the list of section headers and main points out loud. If this story, spoken, hangs together and is logical and complete — there’s a good chance your fully written story will as well.

Not all elements of your story need citations, but many of them will.

When the storyboard is complete, what should you do next? Sometimes, I hand it to a collaborator to flesh it out. Other times, I’ll put it aside for a few days or weeks, and then pick it up later when my mind is fresh. Whatever approach you use, this will help you organize your thoughts and citations, and help you form a story line that’s complete and understandable. Hope this helps get you started!

STORYBOARD (BLANK)

STORYBOARD (PARTIALLY FILLED IN)

Advertisements

Where Do Z-Score Tables Come From? (+ how to make them in R)

z-score-table-iconEvery student learns how to look up areas under the normal curve using Z-Score tables in their first statistics class. But what is less commonly covered, especially in courses where calculus is not a prerequisite, is where those Z-Score tables come from: figuring out the area under the normal curve for all possible places you could chop it into two, then making a table from it.

You get the z-score by evaluating the integral of the equation for the bell-shaped normal curve, usually from -Inf to the z-score of interest. This is the same thing that the R command pnorm does when you provide it with a z-score. Here is the slide presentation I put together to explain the use and origin of the Z-Score table, and how it relates to pnorm and qnorm (the command that lets you input an area to find the z-score at which the area to the left is swiped out). It’s free to use under Creative Commons, and is part of the course materials that is available for use with this 2017 book.

One of the fun things I did was to make my own z-score table in R. I don’t know why anyone would WANT to do this — they are easy to find in books, and online, and if you know how to use pnorm and qnorm, you don’t need one at all. But, you can, and here’s how.

First, let’s create a z-score table just with left-tail areas. Using symmetry, we can also use this to get any areas in the right tail, because the area to the left of any -z is the same as any area to the right of any +z. Even though the z-score table contains areas in its cells, our first step is to create a table just of the z-scores that correspond to each cell:

c0 <- seq(-3.4,0,.1)
c1 <- seq(-3.41,0,.1)
c2 <- seq(-3.42,0,.1)
c3 <- seq(-3.43,0,.1)
c4 <- seq(-3.44,0,.1)
c5 <- seq(-3.45,0,.1)
c6 <- seq(-3.46,0,.1)
c7 <- seq(-3.47,0,.1)
c8 <- seq(-3.48,0,.1)
c9 <- seq(-3.49,0,.1)
z <- cbind(c0,c1,c2,c3,c4,c5,c6,c7,c8,c9)
z

 c0 c1 c2 c3 c4 c5 c6 c7 c8 c9
 [1,] -3.4 -3.41 -3.42 -3.43 -3.44 -3.45 -3.46 -3.47 -3.48 -3.49
 [2,] -3.3 -3.31 -3.32 -3.33 -3.34 -3.35 -3.36 -3.37 -3.38 -3.39
 [3,] -3.2 -3.21 -3.22 -3.23 -3.24 -3.25 -3.26 -3.27 -3.28 -3.29
 [4,] -3.1 -3.11 -3.12 -3.13 -3.14 -3.15 -3.16 -3.17 -3.18 -3.19
 [5,] -3.0 -3.01 -3.02 -3.03 -3.04 -3.05 -3.06 -3.07 -3.08 -3.09
 [6,] -2.9 -2.91 -2.92 -2.93 -2.94 -2.95 -2.96 -2.97 -2.98 -2.99
 [7,] -2.8 -2.81 -2.82 -2.83 -2.84 -2.85 -2.86 -2.87 -2.88 -2.89
 [8,] -2.7 -2.71 -2.72 -2.73 -2.74 -2.75 -2.76 -2.77 -2.78 -2.79
 [9,] -2.6 -2.61 -2.62 -2.63 -2.64 -2.65 -2.66 -2.67 -2.68 -2.69
[10,] -2.5 -2.51 -2.52 -2.53 -2.54 -2.55 -2.56 -2.57 -2.58 -2.59
[11,] -2.4 -2.41 -2.42 -2.43 -2.44 -2.45 -2.46 -2.47 -2.48 -2.49
[12,] -2.3 -2.31 -2.32 -2.33 -2.34 -2.35 -2.36 -2.37 -2.38 -2.39
[13,] -2.2 -2.21 -2.22 -2.23 -2.24 -2.25 -2.26 -2.27 -2.28 -2.29
[14,] -2.1 -2.11 -2.12 -2.13 -2.14 -2.15 -2.16 -2.17 -2.18 -2.19
[15,] -2.0 -2.01 -2.02 -2.03 -2.04 -2.05 -2.06 -2.07 -2.08 -2.09
[16,] -1.9 -1.91 -1.92 -1.93 -1.94 -1.95 -1.96 -1.97 -1.98 -1.99
[17,] -1.8 -1.81 -1.82 -1.83 -1.84 -1.85 -1.86 -1.87 -1.88 -1.89
[18,] -1.7 -1.71 -1.72 -1.73 -1.74 -1.75 -1.76 -1.77 -1.78 -1.79
[19,] -1.6 -1.61 -1.62 -1.63 -1.64 -1.65 -1.66 -1.67 -1.68 -1.69
[20,] -1.5 -1.51 -1.52 -1.53 -1.54 -1.55 -1.56 -1.57 -1.58 -1.59
[21,] -1.4 -1.41 -1.42 -1.43 -1.44 -1.45 -1.46 -1.47 -1.48 -1.49
[22,] -1.3 -1.31 -1.32 -1.33 -1.34 -1.35 -1.36 -1.37 -1.38 -1.39
[23,] -1.2 -1.21 -1.22 -1.23 -1.24 -1.25 -1.26 -1.27 -1.28 -1.29
[24,] -1.1 -1.11 -1.12 -1.13 -1.14 -1.15 -1.16 -1.17 -1.18 -1.19
[25,] -1.0 -1.01 -1.02 -1.03 -1.04 -1.05 -1.06 -1.07 -1.08 -1.09
[26,] -0.9 -0.91 -0.92 -0.93 -0.94 -0.95 -0.96 -0.97 -0.98 -0.99
[27,] -0.8 -0.81 -0.82 -0.83 -0.84 -0.85 -0.86 -0.87 -0.88 -0.89
[28,] -0.7 -0.71 -0.72 -0.73 -0.74 -0.75 -0.76 -0.77 -0.78 -0.79
[29,] -0.6 -0.61 -0.62 -0.63 -0.64 -0.65 -0.66 -0.67 -0.68 -0.69
[30,] -0.5 -0.51 -0.52 -0.53 -0.54 -0.55 -0.56 -0.57 -0.58 -0.59
[31,] -0.4 -0.41 -0.42 -0.43 -0.44 -0.45 -0.46 -0.47 -0.48 -0.49
[32,] -0.3 -0.31 -0.32 -0.33 -0.34 -0.35 -0.36 -0.37 -0.38 -0.39
[33,] -0.2 -0.21 -0.22 -0.23 -0.24 -0.25 -0.26 -0.27 -0.28 -0.29
[34,] -0.1 -0.11 -0.12 -0.13 -0.14 -0.15 -0.16 -0.17 -0.18 -0.19
[35,] 0.0 -0.01 -0.02 -0.03 -0.04 -0.05 -0.06 -0.07 -0.08 -0.09

Now that we have slots for all the z-scores, we can use pnorm to transform all those values into the areas that are swiped out to the left of that z-score. This part is easy, and only takes one line. The remaining three lines format and display the z-score table:

zscore.df <- round(pnorm(z),4)
row.names(zscore.df) <- sprintf("%.2f", c0)
colnames(zscore.df) <- seq(0,0.09,0.01)
zscore.df

 0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09
-3.40 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0002
-3.30 0.0005 0.0005 0.0005 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0003
-3.20 0.0007 0.0007 0.0006 0.0006 0.0006 0.0006 0.0006 0.0005 0.0005 0.0005
-3.10 0.0010 0.0009 0.0009 0.0009 0.0008 0.0008 0.0008 0.0008 0.0007 0.0007
-3.00 0.0013 0.0013 0.0013 0.0012 0.0012 0.0011 0.0011 0.0011 0.0010 0.0010
-2.90 0.0019 0.0018 0.0018 0.0017 0.0016 0.0016 0.0015 0.0015 0.0014 0.0014
-2.80 0.0026 0.0025 0.0024 0.0023 0.0023 0.0022 0.0021 0.0021 0.0020 0.0019
-2.70 0.0035 0.0034 0.0033 0.0032 0.0031 0.0030 0.0029 0.0028 0.0027 0.0026
-2.60 0.0047 0.0045 0.0044 0.0043 0.0041 0.0040 0.0039 0.0038 0.0037 0.0036
-2.50 0.0062 0.0060 0.0059 0.0057 0.0055 0.0054 0.0052 0.0051 0.0049 0.0048
-2.40 0.0082 0.0080 0.0078 0.0075 0.0073 0.0071 0.0069 0.0068 0.0066 0.0064
-2.30 0.0107 0.0104 0.0102 0.0099 0.0096 0.0094 0.0091 0.0089 0.0087 0.0084
-2.20 0.0139 0.0136 0.0132 0.0129 0.0125 0.0122 0.0119 0.0116 0.0113 0.0110
-2.10 0.0179 0.0174 0.0170 0.0166 0.0162 0.0158 0.0154 0.0150 0.0146 0.0143
-2.00 0.0228 0.0222 0.0217 0.0212 0.0207 0.0202 0.0197 0.0192 0.0188 0.0183
-1.90 0.0287 0.0281 0.0274 0.0268 0.0262 0.0256 0.0250 0.0244 0.0239 0.0233
-1.80 0.0359 0.0351 0.0344 0.0336 0.0329 0.0322 0.0314 0.0307 0.0301 0.0294
-1.70 0.0446 0.0436 0.0427 0.0418 0.0409 0.0401 0.0392 0.0384 0.0375 0.0367
-1.60 0.0548 0.0537 0.0526 0.0516 0.0505 0.0495 0.0485 0.0475 0.0465 0.0455
-1.50 0.0668 0.0655 0.0643 0.0630 0.0618 0.0606 0.0594 0.0582 0.0571 0.0559
-1.40 0.0808 0.0793 0.0778 0.0764 0.0749 0.0735 0.0721 0.0708 0.0694 0.0681
-1.30 0.0968 0.0951 0.0934 0.0918 0.0901 0.0885 0.0869 0.0853 0.0838 0.0823
-1.20 0.1151 0.1131 0.1112 0.1093 0.1075 0.1056 0.1038 0.1020 0.1003 0.0985
-1.10 0.1357 0.1335 0.1314 0.1292 0.1271 0.1251 0.1230 0.1210 0.1190 0.1170
-1.00 0.1587 0.1562 0.1539 0.1515 0.1492 0.1469 0.1446 0.1423 0.1401 0.1379
-0.90 0.1841 0.1814 0.1788 0.1762 0.1736 0.1711 0.1685 0.1660 0.1635 0.1611
-0.80 0.2119 0.2090 0.2061 0.2033 0.2005 0.1977 0.1949 0.1922 0.1894 0.1867
-0.70 0.2420 0.2389 0.2358 0.2327 0.2296 0.2266 0.2236 0.2206 0.2177 0.2148
-0.60 0.2743 0.2709 0.2676 0.2643 0.2611 0.2578 0.2546 0.2514 0.2483 0.2451
-0.50 0.3085 0.3050 0.3015 0.2981 0.2946 0.2912 0.2877 0.2843 0.2810 0.2776
-0.40 0.3446 0.3409 0.3372 0.3336 0.3300 0.3264 0.3228 0.3192 0.3156 0.3121
-0.30 0.3821 0.3783 0.3745 0.3707 0.3669 0.3632 0.3594 0.3557 0.3520 0.3483
-0.20 0.4207 0.4168 0.4129 0.4090 0.4052 0.4013 0.3974 0.3936 0.3897 0.3859
-0.10 0.4602 0.4562 0.4522 0.4483 0.4443 0.4404 0.4364 0.4325 0.4286 0.4247
0.00 0.5000 0.4960 0.4920 0.4880 0.4840 0.4801 0.4761 0.4721 0.4681 0.4641

You can also draw a picture to go along with your z-score table, so that people remember which area they are looking up:

x <- seq(-4,4,0.1)
y <- dnorm(x)
plot(x,dnorm(x),type="l", col="black", lwd=3)
abline(v=-1,lwd=3,col="blue")
abline(h=0,lwd=3,col="black")
polygon(c(x[1:31],rev(x[1:31])), c(rep(0,31),rev(y[1:31])), col="lightblue")

It looks like this:

z-score-table-icon-small

In the slides, code to produce a giant-tail z-score table is also provided (where the areas are > 50%).

The Value of Defining Context

Image Credit: Doug Buckley of http://hyperactive.to

Image Credit: Doug Buckley of http://hyperactive.to

The most important stage of problem-solving in organizations is often one of the earliest: getting everyone on the same page by defining the concepts, processes, and desired outcomes that are central to understanding the problem and formulating a solution. (“Everyone” can be the individuals on a project team, or the individuals that contribute actions to a process, or both.) Too often, we assume that the others around us see and experience the world the same way we do. In many cases, our assessments are not too far apart, which is how most people can get away with making this assumption on a regular basis.

In fact, some people experience things so differently that they don’t even “picture” anything in their minds. Can you believe it?

I first realized this divergence in the work context a few years ago, when a colleague and I were advising a project at a local social services office. We asked our students to document the process that was being used to process claims. There were nearly ten people who were part of this claims-processing activity, and our students interviewed all of them, discovering that each person had a remarkably different idea about the process that they were all engaged in! No wonder the claims processing time was nearly two months long.

We helped them all — literally — get onto the same page, and once they all had the same mental map of the process, time-in-system for each claim dropped to 10 days. (This led us to the quantum-esque conclusion that there is no process until it is observed.)

Today, I read about how mathematician Keith Devlin revolutionized the process of intelligence gathering after 9/11 using this same approach… by going back to one of the first principles he learned in his academic training:

So what had I done? Nothing really — from my perspective. My task was to find a way of analyzing how context influences data analysis and reasoning in highly complex domains involving military, political, and social contexts. I took the oh-so-obvious (to me) first step. I need to write down as precise a mathematical definition as possible of what a context is. It took me a couple of days…I can’t say I was totally satisfied with it…but it was the best I could do, and it did at least give me a firm base on which to start to develop some rudimentary mathematical ideas.

The fairly large group of really smart academics, defense contractors, and senior DoD personnel spent the entire hour of my allotted time discussing that one definition. The discussion brought out that all the different experts had a different conception of what a context is — a recipe for disaster.

What I had given them was, first, I asked the question “What is a context?” Since each person in the room besides me had a good working concept of context — different ones, as I just noted — they never thought to write down a formal definition. It was not part of what they did. And second, by presenting them with a formal definition, I gave them a common reference point from which they could compare and contrast their own notions. There we had the beginnings of disaster avoidance.

Getting people to very precisely understand the definitions, concepts, processes, and desired outcomes that are central to a problem might take some time and effort, but it is always extremely valuable.

When you face a situation like this in mathematics, you spend a lot of time going back to the basics. You ask questions like, “What do these words mean in this context?” and, “What obvious attempts have already been ruled out, and why?” More deeply, you’d ask, “Why are these particular open questions important?” and, “Where do they see this line of inquiry leading?”

(You can read the full article about Devlin, and more important lessons from mathematical thinking, Here.)

View story at Medium.com

Innovation Tips for Strategic Planning

Image Credit: Doug Buckley of http://hyperactive.to

Image Credit: Doug Buckley of http://hyperactive.to

Over the past 15 years, I’ve helped several organizations with continuous improvement initiatives at the strategic, executive level. There are a lot of themes that keep appearing and reappearing, so the purpose of this post is to call out just a few and provide some insights in how to deal with them! 

These come up when you are engaged in strategic planning and when you are planning operations (to ensure that processes and procedures ultimately satisfy strategic goals), and are especially prominent when you’re trying to develop or use Key Performance Indicators (KPIs) and other metrics or analytics.

 

1) How do you measure innovation? Before you pick metrics, recognize that the answer to this question depends on how you articulate the strategic goals for your innovation outcomes. Do you want to:

  • Keep up with changing technology?
  • Develop a new product/technology?
  • Lead your industry in developing best practices?
  • Pioneer new business models?
  • Improve quality of life for a particular group of people?

All of these will be measured in different ways! And it’s OK to not strategically innovate in one area or another… for example, you might not want to innovate your business model if technology development is your forte. Innovation is one of those things where you really don’t want to be everything to everyone… by design.

 

2) Do you distinguish between improving productivity and generating impact?

Improving quality (the ability to satisfy stated and implied needs) is good. Improving productivity (that is, what you can produce given the resources that you use) is also good. Reducing defects, reducing waste, and reducing variation (sometimes) are all very good things to do, and to report on. 

But who really cares about any improvements at all unless they have impact? It’s always necessary to tie your KPIs, which are often measures of outcomes, to metrics or analytics that can tell the story about why a particular improvement was useful — in the short term, and (hopefully also) in the long term.

You also have to balance productivity and impact. For example, maybe you run an ultra-efficient 24/7 Help Desk. Your effectiveness is exemplary… when someone submits a request, it’s always satisfied within 8 hours. But you discover that no tickets come in between Friday at 5pm and Monday at 8am. So all that time you spend staffing that Help Desk on the weekend? It’s non-value-added time, and could be eliminated to improve your productivity… but won’t influence your impact at all.

We just worked on a project where we had to consciously had to think about how all the following interact… and you should too:

  • Organizational Productivity: did your improvement help increase the capacity or capability for part of your organization? If so, then it could contribute to technical productivity or business productivity.
  • Technical Productivity: did the improvement remove a technical barrier to getting work done, or make it faster or less error-prone?
  • Business Productivity: did the improvement help you get the needs of the business satisfied faster or better?
  • Business Impact: Did the improvements that yielded organizational productivity benefits, technical productivity benefits, or business productivity benefits make a difference at the strategic level? (This answers the “so what” question. So you improved your throughput by 83%… so what? Who really cares, and why does this matter to them? Long-term, why does this awesome thing you did really matter?)
  • Educational/Workforce Development Impact: Were the lessons learned captured, fed back into the organization’s processes to close the loop on learning, or maybe even used to educate people who may become part of your workforce pipeline?

All of the categories above are interrelated. I don’t think you can have a comprehensive, innovation-focused analytics approach unless you address all of these.

 

3) Do you distinguish between participation and engagement?

Participation means you showed up. Engagement means you got involved, you stayed involved, your mission was advanced, or maybe you used this experience to help society. Too often, I see organizations that want to improve engagement, and all the metrics they select are really good at characterizing participation.

I’m writing a paper on this topic right now, but in the meantime (if you want to get a REALLY good sense of the difference between participation and engagement), read The Participatory Museum by Nina Simon. Yes, it is “about museums” — and yes, I know you’re in business or industry — and YES, this book really will provide you with amazing management insights. So read it!

Analytic Hierarchy Process (AHP) using preferenceFunction in ahp

Yesterday, I wrote about how to use gluc‘s new ahp package on a simple Tom-Dick-Harry one level decision making problem using Analytic Hierarchy Process (AHP). One of the cool things about that package is that in addition to specifying the pairwise comparisons directly using Saaty’s scale (below, from https://kristalaace2014.wordpress.com/2014/05/14/w12_al_vendor-evaluation/)…

saaty-scale

…you can also describe each of the Alternatives in terms of descriptive variables which you can use inside a function to make the pairwise comparisons automatically. This is VERY helpful if you have lots of criteria, subcriteria, or alternatives to evaluate!! For example, I used preferenceFunction to compare 55 alternatives using 6 criteria and 4 subcriteria, and was very easily able to create functions to represent my judgments. This was much easier than manually entering all the comparisons.

This post shows HOW I replaced some of my manual comparisons with automated comparisons using preferenceFunction. (The full YAML file is included at the bottom of this post for you to use if you want to run this example yourself.) First, recall that the YAML file starts with specifying the alternatives that you are trying to choose from (at the bottom level of the decision hierarchy) and some variables that characterize those alternatives. I used the descriptions in the problem statement to come up with some assessments between 1=not great and 10=great:

#########################
# Alternatives Section
# THIS IS FOR The Tom, Dick, & Harry problem at
# https://en.wikipedia.org/wiki/Analytic_hierarchy_process_%E2%80%93_leader_example
#
Alternatives: &alternatives
# 1= not well; 10 = best possible
# Your assessment based on the paragraph descriptions may be different.
  Tom:
    age: 50
    experience: 7
    education: 4
    leadership: 10
  Dick:
    age: 60
    experience: 10
    education: 6
    leadership: 6
  Harry:
    age: 30
    experience: 5
    education: 8
    leadership: 6
#
# End of Alternatives Section
#####################################

Here is a snippet from my original YAML file specifying my AHP problem manually ():

  children: 
    Experience:
      preferences:
        - [Tom, Dick, 1/4]
        - [Tom, Harry, 4]
        - [Dick, Harry, 9]
      children: *alternatives
    Education:
      preferences:
        - [Tom, Dick, 3]
        - [Tom, Harry, 1/5]
        - [Dick, Harry, 1/7]
      children: *alternatives

And here is what I changed that snippet to, so that it would do my pairwise comparisons automatically. The functions are written in standard R (fortunately), and each function has access to a1 and a2 (the two alternatives). Recursion is supported which makes this capability particularly useful. I tried to write a function using two of the characteristics in the decision (a1$age and a1$experience) but this didn’t seen to work. I’m not sure whether the package supports it or not. Here are my comparisons rewritten as functions:

  children: 
    Experience:
          preferenceFunction: >
            ExperiencePreference <- function(a1, a2) {
              if (a1$experience < a2$experience) return (1/ExperiencePreference(a2, a1))
              ratio <- a1$experience / a2$experience
              if (ratio < 1.05) return (1)
              if (ratio < 1.2) return (2)
              if (ratio < 1.5) return (3)
              if (ratio < 1.8) return (4)
              if (ratio < 2.1) return (5) return (6) } children: *alternatives Education: preferenceFunction: >
            EducPreference <- function(a1, a2) {
              if (a1$education < a2$education) return (1/EducPreference(a2, a1))
              ratio <- a1$education / a2$education
              if (ratio < 1.05) return (1)
              if (ratio < 1.15) return (2)
              if (ratio < 1.25) return (3)
              if (ratio < 1.35) return (4)
              if (ratio < 1.55) return (5)
              return (5)
            }
          children: *alternatives

To run the AHP with functions in R, I used this code (I am including the part that gets the ahp package, in case you have not done that yet). BE CAREFUL and make sure, like in FORTRAN, that you line things up so that the words START in the appropriate columns. For example, the “p” in preferenceFunction MUST be immediately below the 7th character of your criterion’s variable name.

devtools::install_github("gluc/ahp", build_vignettes = TRUE)
install.packages("data.tree")

library(ahp)
library(data.tree)

setwd("C:/AHP/artifacts")
nofxnAhp <- LoadFile("tomdickharry.txt")
Calculate(nofxnAhp)
fxnAhp <- LoadFile("tomdickharry-fxns.txt")
Calculate(fxnAhp)

print(nofxnAhp, "weight")
print(fxnAhp, "weight")

You can see that the weights are approximately the same, indicating that I did a good job at developing functions that represent the reality of how I used the variables attached to the Alternatives to make my pairwise comparisons. The results show that Dick is now the best choice, although there is some inconsistency in our judgments for Experience that we should examine further. (I have not examined this case to see whether rank reversal could be happening).

> print(nofxnAhp, "weight")
                         levelName     weight
1  Choose the Most Suitable Leader 1.00000000
2   ¦--Experience                  0.54756924
3   ¦   ¦--Tom                     0.21716561
4   ¦   ¦--Dick                    0.71706504
5   ¦   °--Harry                   0.06576935
6   ¦--Education                   0.12655528
7   ¦   ¦--Tom                     0.18839410
8   ¦   ¦--Dick                    0.08096123
9   ¦   °--Harry                   0.73064467
10  ¦--Charisma                    0.26994992
11  ¦   ¦--Tom                     0.74286662
12  ¦   ¦--Dick                    0.19388163
13  ¦   °--Harry                   0.06325174
14  °--Age                         0.05592555
15      ¦--Tom                     0.26543334
16      ¦--Dick                    0.67162545
17      °--Harry                   0.06294121

> print(fxnAhp, "weight")
                         levelName     weight
1  Choose the Most Suitable Leader 1.00000000
2   ¦--Experience                  0.54756924
3   ¦   ¦--Tom                     0.25828499
4   ¦   ¦--Dick                    0.63698557
5   ¦   °--Harry                   0.10472943
6   ¦--Education                   0.12655528
7   ¦   ¦--Tom                     0.08273483
8   ¦   ¦--Dick                    0.26059839
9   ¦   °--Harry                   0.65666678
10  ¦--Charisma                    0.26994992
11  ¦   ¦--Tom                     0.74286662
12  ¦   ¦--Dick                    0.19388163
13  ¦   °--Harry                   0.06325174
14  °--Age                         0.05592555
15      ¦--Tom                     0.26543334
16      ¦--Dick                    0.67162545
17      °--Harry                   0.06294121

> ShowTable(fxnAhp)

tomdick-ahp-fxns

Here is the full YAML file for the “with preferenceFunction” case.

#########################
# Alternatives Section
# THIS IS FOR The Tom, Dick, & Harry problem at
# https://en.wikipedia.org/wiki/Analytic_hierarchy_process_%E2%80%93_leader_example
#
Alternatives: &alternatives
# 1= not well; 10 = best possible
# Your assessment based on the paragraph descriptions may be different.
  Tom:
    age: 50
    experience: 7
    education: 4
    leadership: 10
  Dick:
    age: 60
    experience: 10
    education: 6
    leadership: 6
  Harry:
    age: 30
    experience: 5
    education: 8
    leadership: 6
#
# End of Alternatives Section
#####################################
# Goal Section
#
Goal:
# A Goal HAS preferences (within-level comparison) and HAS Children (items in level)
  name: Choose the Most Suitable Leader
  preferences:
    # preferences are defined pairwise
    # 1 means: A is equal to B
    # 9 means: A is highly preferrable to B
    # 1/9 means: B is highly preferrable to A
    - [Experience, Education, 4]
    - [Experience, Charisma, 3]
    - [Experience, Age, 7]
    - [Education, Charisma, 1/3]
    - [Education, Age, 3]
    - [Age, Charisma, 1/5]
  children: 
    Experience:
          preferenceFunction: >
            ExperiencePreference <- function(a1, a2) {
              if (a1$experience < a2$experience) return (1/ExperiencePreference(a2, a1))
              ratio <- a1$experience / a2$experience
              if (ratio < 1.05) return (1)
              if (ratio < 1.2) return (2)
              if (ratio < 1.5) return (3)
              if (ratio < 1.8) return (4)
              if (ratio < 2.1) return (5) return (6) } children: *alternatives Education: preferenceFunction: >
            EducPreference <- function(a1, a2) {
              if (a1$education < a2$education) return (1/EducPreference(a2, a1))
              ratio <- a1$education / a2$education
              if (ratio < 1.05) return (1)
              if (ratio < 1.15) return (2)
              if (ratio < 1.25) return (3)
              if (ratio < 1.35) return (4)
              if (ratio < 1.55) return (5)
              return (5)
            }
          children: *alternatives
    Charisma:
      preferences:
        - [Tom, Dick, 5]
        - [Tom, Harry, 9]
        - [Dick, Harry, 4]
      children: *alternatives
    Age:
      preferences:
        - [Tom, Dick, 1/3]
        - [Tom, Harry, 5]
        - [Dick, Harry, 9]
      children: *alternatives
#
# End of Goal Section
#####################################

Analytic Hierarchy Process (AHP) with the ahp Package

On my December to-do list, I had “write an R package to make analytic hierarchy process (AHP) easier” — but fortunately gluc beat me to it, and saved me tons of time that I spent using AHP to do an actual research problem. First of all, thank you for writing the new ahp package! Next, I’d like to show everyone just how easy this package makes performing AHP and displaying the results. We will use the Tom, Dick, and Harry example that is described on Wikipedia. – the goal is to choose a new employee, and you can pick either Tom, Dick, or Harry. Read the problem statement on Wikipedia before proceeding.

AHP is a method for multi-criteria decision making that breaks the problem down based on decision criteria, subcriteria, and alternatives that could satisfy a particular goal. The criteria are compared to one another, the alternatives are compared to one another based on how well they comparatively satisfy the subcriteria, and then the subcriteria are examined in terms of how well they satisfy the higher-level criteria. The Tom-Dick-Harry problem is a simple hierarchy: only one level of criteria separates the goal (“Choose the Most Suitable Leader”) from the alternatives (Tom, Dick, or Harry):

tom-dick-harry

To use the ahp package, the most challenging part involves setting up the YAML file with your hierarchy and your rankings. THE MOST IMPORTANT THING TO REMEMBER IS THAT THE FIRST COLUMN IN WHICH A WORD APPEARS IS IMPORTANT. This feels like FORTRAN. YAML experts may be appalled that I just didn’t know this, but I didn’t. So most of the first 20 hours I spent stumbling through the ahp package involved coming to this very critical conclusion. The YAML AHP input file requires you to specify 1) the alternatives (along with some variables that describe the alternatives; I didn’t use them in this example, but I’ll post a second example that does use them) and 2) the goal hierarchy, which includes 2A) comparisons of all the criteria against one another FIRST, and then 2B) comparisons of the criteria against the alternatives. I saved my YAML file as tomdickharry.txt and put it in my C:/AHP/artifacts directory:

#########################
# Alternatives Section
# THIS IS FOR The Tom, Dick, & Harry problem at
# https://en.wikipedia.org/wiki/Analytic_hierarchy_process_%E2%80%93_leader_example
#
Alternatives: &alternatives
# 1= not well; 10 = best possible
# Your assessment based on the paragraph descriptions may be different.
  Tom:
    age: 50
    experience: 7
    education: 4
    leadership: 10
  Dick:
    age: 60
    experience: 10
    education: 6
    leadership: 6
  Harry:
    age: 30
    experience: 5
    education: 8
    leadership: 6
#
# End of Alternatives Section
#####################################
# Goal Section
#
Goal:
# A Goal HAS preferences (within-level comparison) and HAS Children (items in level)
  name: Choose the Most Suitable Leader
  preferences:
    # preferences are defined pairwise
    # 1 means: A is equal to B
    # 9 means: A is highly preferable to B
    # 1/9 means: B is highly preferable to A
    - [Experience, Education, 4]
    - [Experience, Charisma, 3]
    - [Experience, Age, 7]
    - [Education, Charisma, 1/3]
    - [Education, Age, 3]
    - [Age, Charisma, 1/5]
  children: 
    Experience:
      preferences:
        - [Tom, Dick, 1/4]
        - [Tom, Harry, 4]
        - [Dick, Harry, 9]
      children: *alternatives
    Education:
      preferences:
        - [Tom, Dick, 3]
        - [Tom, Harry, 1/5]
        - [Dick, Harry, 1/7]
      children: *alternatives
    Charisma:
      preferences:
        - [Tom, Dick, 5]
        - [Tom, Harry, 9]
        - [Dick, Harry, 4]
      children: *alternatives
    Age:
      preferences:
        - [Tom, Dick, 1/3]
        - [Tom, Harry, 5]
        - [Dick, Harry, 9]
      children: *alternatives
#
# End of Goal Section
#####################################

Next, I installed gluc’s ahp package and a helper package, data.tree, then loaded them into R:

devtools::install_github("gluc/ahp", build_vignettes = TRUE)
install.packages("data.tree")

library(ahp)
library(data.tree)

Running the calculations was ridiculously easy:

setwd("C:/AHP/artifacts")
myAhp <- LoadFile("tomdickharry.txt")
Calculate(myAhp)

And then generating the output was also ridiculously easy:

> GetDataFrame(myAhp)
                                  Weight  Dick   Tom Harry Consistency
1 Choose the Most Suitable Leader 100.0% 49.3% 35.8% 14.9%        4.4%
2  ¦--Experience                   54.8% 39.3% 11.9%  3.6%        3.2%
3  ¦--Education                    12.7%  1.0%  2.4%  9.2%        5.6%
4  ¦--Charisma                     27.0%  5.2% 20.1%  1.7%        6.1%
5  °--Age                           5.6%  3.8%  1.5%  0.4%        2.5%
> 
> print(myAhp, "weight", filterFun = isNotLeaf)
                        levelName     weight
1 Choose the Most Suitable Leader 1.00000000
2  ¦--Experience                  0.54756924
3  ¦--Education                   0.12655528
4  ¦--Charisma                    0.26994992
5  °--Age                         0.05592555
> print(myAhp, "weight")
                         levelName     weight
1  Choose the Most Suitable Leader 1.00000000
2   ¦--Experience                  0.54756924
3   ¦   ¦--Tom                     0.21716561
4   ¦   ¦--Dick                    0.71706504
5   ¦   °--Harry                   0.06576935
6   ¦--Education                   0.12655528
7   ¦   ¦--Tom                     0.18839410
8   ¦   ¦--Dick                    0.08096123
9   ¦   °--Harry                   0.73064467
10  ¦--Charisma                    0.26994992
11  ¦   ¦--Tom                     0.74286662
12  ¦   ¦--Dick                    0.19388163
13  ¦   °--Harry                   0.06325174
14  °--Age                         0.05592555
15      ¦--Tom                     0.26543334
16      ¦--Dick                    0.67162545
17      °--Harry                   0.06294121

You can also generate very beautiful output with the command below (but you’ll have to run the example yourself if you want to see how fantastically it turns out — maybe that will provide some motivation!)

ShowTable(myAhp)

I’ll post soon with an example of how to use AHP preference functions in the Tom, Dick, & Harry problem.

Course Materials for Statistics (The Easier Way) With R

very-quick-cover-outlineAre you an instructor with a Spring 2016 intro to statistics course coming up… and yet you haven’t started preparing? If so, I have a potential solution for you to consider. The materials (lecture slides, in-class practice problems in R, exams, syllabus) go with my book and are about 85% compiled, but good enough to get a course started this week (I will be finishing the collection by mid-January).
There is also a 36MB .zip file if you would like to download the materials.
Whether you will be using them or just considering them, please fill in the Google Form at https://docs.google.com/forms/d/1Z7djuKHg1L4k7bTtktHXI7Juduad3fUW9G69bxN6jRA/viewform so I can keep track of everyone and provide you with updates. Also, I want to make sure that I’m providing the materials to INSTRUCTORS (and not students), so please use the email account from your institution when you sign up. Once I get your contact information, I will email you the link to the materials.
If you would like permission to edit the materials, I can do that as well — I know a couple of you have expressed that you would like to add to the collection (e.g translate them to another language). If you see any issues or errors, please either fix and/or email to tell me to fix!
Thanks for your interest and participation! Also, Happy New Year!
« Older Entries