Nov
22
An Attitude of Gratitude
November 22, 2015 | 4 Comments
It’s been a pleasure speaking to groups around North Dakota this past week, in part because I was asked a lot of intelligent questions, which really forced me to think about the answers.
One young woman asked how I maintained a positive attitude when times were difficult, when my husband died, when there is a seeming unending pile of work to do, when my children are heading in what I think is the wrong direction.
The answer is that I try every day to wake up grateful, and it really is pretty easy if you are realistic and honest about your situation.
Read any history book – and not ancient history, either – about people breaking the film of ice on the pan of water IN THEIR HOUSE, as they started their day, to wash clothes or make coffee.
Even today, people wake up sleeping under bridges, on the ground in refugee camps. I’ve lived in old houses where the wind blows through cracks in the winter.
North Dakota is cold and for almost the entire history of the world there wasn’t much anyone could do about it. Yes, people discovered fire, hunted, had deer skins, tipis. However, it was nothing like the last few days when I woke up every morning, warm and comfortable, in well-insulated houses, on soft mattresses under a pile of quilts.
Being at Minot State University reminded me of my own graduate school days at the University of Minnesota. They had tunnels under the campus, connecting buildings, for which I was extremely grateful because I was a broke, graduate student and I didn’t have enough money to buy a lot of warm clothes. Any time I had to go outside between buildings, I was SO cold.
These days, buying long underwear, gloves, warm coats, is something I don’t even give a thought. If I need it, I get it. Half the clothes I didn’t even buy – my daughters gave me sweaters and coats for Christmas or because they had more than they could use.
Maybe you think it’s silly to wake up grateful that I have warm clothes and a soft bed in a warm house, but I think it’s objective. There was a point in my life when I had neither. Most of the people who ever lived on this earth had nowhere near the level of comfort that I wake up to every day. If they (or me, decades ago), could be magically picked up and dropped into my life, their first thought on waking up would be,
“Oh my God, this is amazing!”
After laying in bed with that thought for a few minutes, I get out of bed.
Nov
22
This is not an abandoned blog
November 22, 2015 | 1 Comment
Years ago, a friend of mine was in college and had an old, beat up car that leaked oil on to the street where it was parked, which, for some reason annoyed her elderly neighbor. When we returned from a trip overseas competing for the U.S., there was a notice on her car – the neighbor had reported the car as abandoned and we got home just in time to stop the city from towing it away. As a joke, the coach got her a bumper sticker that read, “This is not an abandoned vehicle.”
It’s almost two weeks since I last posted. Contrary to appearances, this is not an abandoned blog!
I just this minute – hurray, tap-dancing – submitted a grant I’ve been working on for the past two weeks.
While writing the grant this week, I’ve been in North Dakota, first giving a presentation on Using Native American Culture to Increase Math Performance. You can see a bit of it that was shown on the local TV station here.
After meeting lots of students at Minot State, we headed over to the Minot Job Corps and I met with students and faculty, talking about our games, starting a company and life in general.
On to New Town, on the Fort Berthold Reservation where I met with the staff and students from the Boys and Girls Club, again, gave demonstrations of our games, and threw a judo demonstration in along with it.
Along there somewhere, I finished the final report on our Dakota Math project that once again found significant improvement in performance of students who played our games, hired two more employees, signed another consulting contract, had way too many meetings and squashed a few bugs in the games.
Tomorrow, I head home to Santa Monica, for two weeks, until I head out to Fort Totten, ND. In the meantime, I’m back to blogging. Did you miss me?
—-
If you want to see what I’m working on these days, you can check it out here:
If you buy a game this week, we’ll throw in a beta release of Forgotten Trail for free!
Nov
9
Is it sick to get this excited about data analysis?
November 9, 2015 | 2 Comments
The results are in! The chart below gladdens my little heart, somewhat.
One thing to note is the fact that the 95% confidence interval is comfortably above zero. Another point is that it looks like a pretty normal distribution.
What is it? It is the difference between pretest and post-test scores for 71 students at two small, rural schools who played Spirit Lake: The Game.
I selected these schools to analyze first, and held my breath. These were the schools we had worked with the most closely, who had implemented the games as we had recommended (play twice a week for 25-30 minutes). If it didn’t work here, it probably wasn’t going to work.
Two years ago, with a sample of 39 students from 4th and 5th grade from one school, we found a significant difference compared to the control group.
COULD WE DO IT AGAIN?
You probably don’t feel nervous reading that statement because you have not spent the last three years of your life developing games that you hope will improve children’s performance in math.
The answer, at least for the first group of data we have analyzed is – YES!
Scores improved 20% from pre-test to post-test. This was not as impressive as the improvement of 30% we had found in the first year, but this group also began with a substantially higher score. Two years ago, the average student scored 39% on the pre-test. This year, for 71 students with complete data, the average pre-test score was 47.9% , the post-test mean was 57.4%. I started this post saying my little heart was gladdened “somewhat” because I still want to see the students improve more.
There is a lot more analysis to do. For a start, there is analysis of data from schools who were not part of our study but who used the pretest and post-test – with them, we can’t really tell how the game was implemented but at least we can get psychometric data on the tests.
We have data on persistence – which we might be able to correlate with post-test data, but I doubt it, since I suspect students who didn’t finish the game probably didn’t take the post-test.
We have data on Fish Lake, which also looks promising.
Overall, it’s just a great day to be a statistician at 7 Generation Games.
Nov
2
SAS Tip: Preventing Disaster When Variable Lengths Differ
November 2, 2015 | 2 Comments
Over the weekend, I wrote a post showing how SAS can be used to make what appears to be a complex problem quite simple.
Simple. You are merging by a variable that is a unique user identifier like username, social security number. Because the two different data sets have different lengths, they do not match. If you are computing the number of unique users you may overestimate by a huge amount. If you want the number of people who are in both data sets, you may vastly underestimate the amount of true matches.
As with anything in programming, there are many ways to do this. My solution is to create a new variable and set it to the identical length and format using the ATTRIB statement. Extra bonus is this will work when you have variables that are not only different lengths but different types, say character in one data set and numeric in the other.
You really only need two statements in your data step, an ATTRIB statement and then an assignment statement that sets the value of the variable you created to whatever the variable is you want to merge.
DATA dsname ;
ATTRIB newvar LENGTH = $49 ;
SET mydata2.dsname ;
newvar = oldvar ;
Repeat this step for the second data set and then merge (or concatenate) to your little heart’s delight.
The voice of experience:
Notice two things here: I created a temporary data set from my permanent one. Although SAS has gotten more forgiving over the years in not writing over your existing data sets when there is an error, it is still better to err on the side of caution and make sure all is wonderful before saving over that existing data, especially if it took you a lot of effort to get the data in that form.
Second, I created a new variable and kept the old one as is. I don’t always do this but it is good practice. You may be tempted to just use the first 9 digits because we all know social security numbers are 9 digits and then later you find that it was entered as 123-45-6789 and now you only have 123-45-67
—- Feel smarter after reading this blog?
Want to feel even smarter? Download and play our games! You can run around in our virtual world while reviewing your basic math skills. If you are too busy (seriously?) you can still give a game as a gift or donate a game to a classroom or school.
Nov
1
Messy Problems Made Simple with SAS
November 1, 2015 | 2 Comments
Some problems that seem really complex are quite simple when you look at them in the right way. Take this one, for example:
My hypothesis is that a major problem in math achievement is persistence. Students just give up at the first sign of trouble. I have three different data sets with student data from the Spirit Lake game. Many of the students in the student table are the control group, so they will have no data on game play. There is a table of answers to the math challenges and another table with answers to quizzes which students took only if they missed a math challenge. When students miss a math challenge in the game, depending on which educational resource they choose, they may do one of two or three different quizzes to get back into the game. Also, some of the quiz records were not from quizzes actually in the game but from supplemental activities we provided. So, how do I identify where in the process students drop out and present in a simple graphic to discuss with schools? Just to complicate matters, the username was different lengths in the different datasets and the variable for timestamp also had different names.
It turns out, the problem was not that difficult.
- Merge the student table with the answers (math challenges) and only include those students with at least one answer.
- Merge the student table with the quizzes and only include those students with at least one quiz
- Concatenate the data sets from steps 1 & 2
- Create a new userid variable and set it equal to the username
- Create a new “entered” variable and set it equal to whichever of the datetime fields exists on that record
- Delete the quizzes not included in the game.
- Sort the dataset by userid and the date and time entered.
- Keep the last record for each userid. Now you have their last date of activity.
- If there is a value for the math challenge field then that is the name of the last activity, otherwise the quiz name is the name for the last activity.
- Use a PROC FORMAT to assign each activity a value equal to the step in the game.
- Do a PROC FREQ using that format and the order = FORMATTED option.
Once I had the frequencies, I just put them into a table in a word document and shaded the columns to match the percentage. There may be a way in SAS/Graph or something else to do this automatically, but honestly, the table took me two minutes once I had the data.
I think it illustrates my points pretty clearly, which are:
- A sizable number of students drop out after the second problem.
- 25% of the students drop after the first difficulty they have (missing the second problem)
- Only a minority of students persist all the way to the end, less than 25% of the total sample
This isn’t based on a tiny sample, either. The data above represent a sample of 397 students.
In case you would like to see it, the code for steps 3-11 is below. Particularly useful is the PROC FORMAT. Notice that you can have multiple values have the same format, which was important here because players can take multiple paths that are still the same step in the sequence.
data persist ;
attrib userid length= $49 ;
set mydata2.sl_answers mydata2.sl_quizzes ;
entered = max(date_answered_dt,date_taken_dt) ;
**** DELETES QUIZZES IN EXTRA AND SUMMER SITE, NOT IN MAIN GAME ;
if quiztype in (“problemsolve”,”divide1long”,”multiplyby23″) then delete ;
userid = new_username ;
format entered datetime20. ;
proc sort data=persist ;
by quiztype ;
proc sort data=persist ;
by userid entered ;
data retention ;
set persist ;
by userid ;
if last.userid ;
attrib last_activity length= $14 ;
if inputform ne “” then last_activity = inputform ;
else last_activity = quiztype ;
proc freq data= retention ;
tables last_activity ;
proc format ;
value
$activity
“findcepansi” = “01”
“x2x9” = “02”
“math2x” = “02”
“math2_2” = “02”
“wolves1a” = “02”
“multiplyby5” = “03”
“multiplyby4” = “03”
“multiplyby3” = “04”
“wolves1b” = “05”
…. AND SO ON ….
“horseform2” = “21”
;
ods rtf file = “C:\Users\Spirit Lake\phaseII\pipeline.rtf” ;
proc freq data= retention order=formatted ;
tables last_activity ;
format last_activity $activity. ;
run ;
ods rtf close ;
Blogroll
- Andrew Gelman's statistics blog - is far more interesting than the name
- Biological research made interesting
- Interesting economics blog
- Love Stats Blog - How can you not love a market research blog with a name like that?
- Me, twitter - Thoughts on stats
- SAS Blog for the rest of us - Not as funny as some, but twice as smart. If this is for the rest of us, who are those other people?
- Simply Statistics, simply interesting
- Tech News that Doesn’t Suck
- The Endeavor -John D Cook - Another statistics blog