I was on a panel about time management for the 2020 INFORMS New Faculty Colloquium (NFC). I recorded a video sharing my tips for time management with assistant professors in mind. I posted my video on YouTube below.
The live Q&A was fantastic, and I learned a lot from my fellow panelists Professors Tom Sharkey and Jonathan Helm. I want to give a big thank you to Professor Siqian Shen, who organized the NFC.
This summer I read Traffic by Tom Vanderbilt and blogged about the OR and networks topics covered in the book. The follow-up post that I promised took nearly three months longer than I thought it would.
For those of you who are familiar with driving and traffic data, you will know that men, on average, drive more than women across all ages, and it’s not even close. Men age 55+ drive more than more than twice as many miles on average as women of the same age. On face value, it seems like men are disproportionately responsible for all the traffic congestion on the road. Tom Vanderbilt challenges this idea in Traffic, looking at why and when women drive rather than looking at how much they drive.
Both men and women drive a lot more than they did in the 1950s, leading to traffic and congestion. There are many reasons for this. Two that are often named are suburban sprawl (people living farther from where they work) and women joining the workforce. This naturally led to an increase in driving by both men and women. Let’s look a bit deeper.
Other things have changed–or not–since the 1950s. One thing that has not changed is that the women who have entered the workforce still do the lion’s share of errands, particularly those involving kids (think: “soccer moms”). In the 1950s, 40% of car trips were work trips. As of ~2010, a mere 16% of car trips were work trips. The difference is not that people aren’t working or taking public transportation to work (they are actually driving to work more!). The difference is that we’ve added many other driving trips to our schedules. And women do more of these extra errands and trips than men do.
Women do a lot of “trip chaining,” stopping at the grocery store on the way to or from work, taking Johnny to soccer practice, etc. The reason why women make such an impact on congestion is because (1) they are taking these trips during peak traffic times due to inflexible schedules, (2) they they use smaller roads less equipped for large traffic loads (these trips do not usually use the interstates), and (3) the distance between trips is significant (suburban sprawl!). Side note: We women are fairly efficient here in that we can minimize travel times by “chaining” – adding a TSP-like “tour” of errands rather than making individual trips that would take longer.
I blogged about the issue of women having inflexible driving routes earlier, where I argue that dropping kids off at day care often makes taking public transportation impossible. Vanderbilt observes this, too. He also does not blame women for the extra traffic, as our travel patterns are what you would expect when considering the demands of both our families and careers. But there are implications.
In all seriousness, this post discussed traffic from the perspective of the “average” men and women. None of us are “average,” of course. The OR tie-in here is that the who, why, where, and when are important for understanding why congestion happens at certain times. The network structure is also important, as traffic network is reflected in trip chaining, and it sheds light on what parts of the network will experience the worst congestion. Vanderbilt’s writing on this topic suggests that encouraging people to contribute less to congestion is challenging, since there are many constraints on women’s driving patterns, and as a result, they might not be able to respond to incentives for reducing the amount they drive.
On a related note: for the first time in the US, the majority of licensed drivers are women.
Related posts:
My husband works for the Federal government. He takes a van pool to and from his work on most days (he has a 120 mile commute round trip). The van pools are a great deal. If someone rides in a van pool, they commit to riding a certain number of days per quarter. They pay a membership fee and are reimbursed for saving gas.
In response to fraud, two significant changes were made to the van pool contracts:
First requirement
The first requirement is a problem. Vacations, has off-site training, goes to a conference, etc, interfere with ridership. Add two of these events together, and you end up with a severely inflexible policy. Employees who have to travel or who want to take a vacation may not be able to abide with the new requirements. Employees that travel a lot may not be the best candidates for the van pool, but employees who have one long trip ever should be able to ride the van.
Second requirement
The second change is even more restrictive. My husband’s van holds 14 people. They need to have at least 8 people ride (7 out of 13 + 1 driver) at least 4 out of 5 days in the week. It’s worth noting that small vans are going to have more of a problem with this because they typically have more variability in who shows up.
Looking at the long-term, a van needs to have at least 8 riders 80% of the time. That implies that the average number of days until the van is not “half” full needs to be 5. If we assume that each day is independent of the others, then we can model this as a geometric distribution. To get the desired average of 5, we need a “success” probability of 1/5. That is, the probability of a van being less than half full on any single day needs to be 20%. Is that realistic?
Let’s look at the 14 riders. Let’s say they each ride each day with probability p and that each day is independent. Then we can model the number of riders each day R~ Binomial(14,p). We need P(R<8) < 0.2 to meet requirement #2 (from the last paragraph). But if p=0.5 (as required), then P(R<8) = 0.605. We need p > 0.642 to get P(R<8) < 0.2.
Thus far, I’ve assumed that each day is independent. Making that assumption will yield optimistic results. The “optimistic” results suggest that even under idealistic assumptions, the new van pool requirements will be extremely difficult to meet.
But this assumption is not valid. Riders ride less on Mondays and Fridays (40% of the work week). In practice, this means a van is likely to have at least 8 riders on three days of the week (Tue-Thu), but not four as required. For simplicity, let’s say that a van always has 8 riders on Tue-Thu (an idealistic assumption, but not too unreasonable). Let’s say that each rider takes the van with probability p = 1/3 on Mondays and Fridays (a modest change), and let’s assume that each rider and day are independent. Then the van has 8 riders with probability 0.0576 on these days. The probability that the van covers at least one Monday or Friday per week is 0.111. Therefore, under more realistic assumptions, it is even more unlikely that a van can meet assumption #2.
Vans could meet these requirements if they “overbook” and allow more riders than there are seats in the van. They will surely need to risk turning riders away to meet their requirements if more than 14 show up some day. This may happen when gas prices change, since ridership increases when gas prices shoot up. However, my husband has noted problems meeting requirement #2 in the past couple of months when gas has been ~$4 per gallon.
Van pools and (un)intended consequences
Van pools are intended to improve the environment by encouraging car pooling. Van pools ultimately create an incentive for people to live very, very far from where they work, thus leading to more fuel usage. In the end, I do not think they save much (or any) fuel from being consumed. But this is open for debate.
On the other hand, van pools are great if your significant other wants a career. It has made our “two body problem” quite manageable. Accommodating one’s spouse’s career is rarely cited as a benefit to van pools. I am grateful that van pools exist so that both my husband and I can have careers. I hope it’s still possible for him to carpool with new rules.
Final thoughts
I applaud the Federal government for trying to crack down on fraud. But I encourage them to create rules that make it possible for riders to follow the letter of the law. And maybe someone who has taken a course on probability should look over the next set of rules and crunches some numbers.
Do you ride a van? Please correct anything I got wrong in the comments and add your two cents about how they can be improved.
ere are five articles about women and engineering. What do these five articles have in common? They were sent to me by men. Thanks guys!
1.Lack of Confidence Spurs Women to leave Engineering
Why do women engineering majors drop out of engineering and switch to other majors? It’s not because women lack competence, it’s because women tend to lack confidence (at least in comparison to their male peers). “As one of the most sex-segregated professions outside the military, engineering carries ingrained notions and biases about men being more naturally suited to the field, which can have self-reinforcing effects.”
A superstar women engineering faculty member whose mannerisms are similar to my own (i.e., she doesn’t ooze confidence) once told/warned me that “a lack of confidence can be interpreted as a lack of competence.” It sounds like it’s not just the men who incorrectly infer–we women internalize this too.
This study doesn’t capture the incoming college students who are deterred for even selecting a science or engineering major, since their high school teachers keep reminding them about how tough and competitive these majors are (see article #4 below). I realize that these “missing” engineering majors are impossible to track, but I find this issue particularly relevant since I started college as a history major (I had particularly low self-confidence in high school). Luckily, I found my way to engineering.
This study has real implications for those of us who are faculty members in STEM fields. Our words and internal biases can have powerful effects. However, we’ve all had a confident alpha male bomb in our classes and have had non-confident, conscientious superstar students, so I hope we know that appearances can be misleading.
2. Engineering blogs: why women don’t go into engineering
A woman’s competence seems to be a function of what she look like and how much makeup she wears.
This blog post makes me cringe because it hits the mark. An interview with this woman engineer was posted online. The first comment about her professional interview was an inappropriate comment about the relative hotness of women in her field. Many women feel uncomfortable in engineering because a few men in engineering always seem to comment on our appearances first. (Note: I am not blaming all or even most men here). I would guess that this is mainly a maturity issue among undergraduates in engineering, which would again create a bad climate for women engineering students. I’m glad that Punk Rock OR attracts more enlightened men.
3.Why women leave the engineering field
A slew of statistical tests using NSF’s data on former engineering majors suggest some interesting findings. The first is that “women actually don’t leave jobs in science at an above average rate. The difference…comes from the engineering sector.” Why do women disproportionately leave engineering but not other scientific fields? The study’s author finds evidence to suggest that being in “a majority-male environment” leads women to leave engineering. The author claims that work-life balance benefits are nice, but they miss the mark when it comes to retaining women in engineering.
4. Working conditions drive women from engineering
Another NSF sponsored study examines why women leave engineering, and it reports similar results. They find that women don’t leave for family reasons nearly as much as we’ve been led to believe. “Nearly half of the women surveyed who left the engineering field said it was because of working conditions and issues such as a lack of career advancement and low salary.” This corroborates some of the findings in the previously listed study.
In 1967, the fashion magazine Cosmopolitan featured an article that urged women to become computer scientists. Yes, this is for real. You should really check this blog post out of only for this pictures. In 1987, 42% of software developers were women. However, women computer science majors dropped from 37% in 1984 to 20% in 2006. In the past couple of years, women CS majors have risen at some of the top universities. This blog post by Fog Creek Software delves into the mystery of why the number of women CS majors has ebbed and flowed. My husband (a programmer) found this part of the blog post relevant and actionable:
[O]ne of the things that happens is that women don’t even think they’re qualified for [a computer science position] because it’s advertised in competitive language. The language of competition not only doesn’t appeal to many women, it actually puts them off. Google advertises their Summer of Code with very competitive language. In 2006, GNOME received almost two hundred GSoC applicants – all male. When GNOME advertised an identical program for women, but emphasizing the opportunities for mentorship and learning, they received over a hundred highly qualified female applicants for the three spots they were able to fund.
I have written about women trailblazers in computing once or twice before. I am still floored by how many women worked for the Bell Labs data center in the 1960s. These retro pictures of computing (1940s – 1960s) also feature women. It’s too bad that when we think of computer scientists, we tend to think of men. Apparently, women have always been an integral part of computer science.
All articles and links were sent to me be men. Hat tips to Hemanshu Kaul, Red Dave, Aaron Ball, and Christopher Felton.
In anticipation of the birth of my third child, I am writing a post about all the ways in which operations research has enriched my views on parenthood and maintain balance.
What am I missing?
Related posts:
After having my third baby last week, I am writing a post on how OR has helped me navigate pregnancy, labor, and birth. Here is a few ways that OR has enhanced my experiences with having babies.
A solid OR background gave me the necessary knowledge about statistics to wade through all of the pregnancy advice out there and keep my perspective. Much of the advice is silly and not evidence-based (like keeping your heart rate < 140 bpm, not lying on your back in a low-risk pregnancy, omitting all caffeine, avoiding certain foods, etc.). Yet some of the best pregnancy advice (like eating your vegetables and staying active) is rarely verbalized.
A solid OR background also means that my educational background alone makes me a likely candidate to avoid most pregnancy complications (education of the mother is almost always a statistically significant factor that is negatively correlated with most adverse pregnancy outcomes).
I know that pregnancy statistics based on aggregate data are almost useless when on my third pregnancy. It’s all about correlation at this point.
After having two labors shorter than average, my midwife told me not to necessarily expect an even shorter labor. After some discussion, I realized she was explaining that anecdotally, she has observed that most women experience regression to the mean after very short labors. That makes sense. If I had a good draw the last time, the odds are, I won’t get as good of a draw this time. In general, buying into the Flaw of Averages is a bad idea for preparing for labor. Few labors are “average.” However, I don’t have a good approach for managing the anxiety that comes along with having to prepare for a myriad of labor realizations. (I ended up having my shortest labor this time).
I have found Bayes rule to be extremely helpful for managing prenatal anxiety. Many screening tests are performed during pregnancy. The one that perhaps causes the most anxiety in expectant moms is the quad screening test, which attempts to screen for Downs syndrome and spina bifida. Given that the test comes back positive, for example, a baby has about a 3% chance of having Downs Syndrome (although I recently learned that these odds vary according to the age of the mother). My quad screen tests came back negative for all three pregnancies, but I was prepared not to panic just in case. A similar screening test is done for gestational diabetes. I had a false positive once and took the dreaded three hour glucose test. That was no fun, but again, I knew not to worry.
My last two deliveries took place at the tail end of a brief surge in births at the hospital (births should be a Poisson process–see my post on the exponential distribution). This meant that all of the recovery rooms in the hospital were occupied by the time I needed one (!) Luckily, I was able to get into a room both times, although this time, I am indebted to two kind nurses who pulled a few strings for me. My hospital stay illustrates that hospitals still need lots of OR for planning hospital beds. (My hospital stay also suggests that OR could be used to schedule meal deliveries, schedule infant inspections, and organize hospital discharges).
With regard to hospital discharges, the bottleneck in the process is waiting for someone with a wheelchair to take me and baby to the car after discharge. This was also true three years ago after my last birth. I would have thought that the bottleneck would be scheduling the “important” stuff, like the pediatrician’s checkup of the baby and the nurse’s checkup of me. Despite being tired after having a baby, I couldn’t help but start to model the hospital system and mentally note where they need to make improvements.
I have avoided amniocentesis for all of my pregnancies, but if I was offered amniocentesis, I would use a decision tree with my personalized economic model to make the decision.
And most importantly, decision analysis methods confirm that it was a good idea for me to be fruitful and multiply.
I am not an expert on the status of men and women in OR/MS, but I have two observations to offer.
1. I was surprised to see that no women attended the social networking session at INFORMS (three women were on the panel).
2. I was surprised to see that several men attended the work-life balance session at INFORMS. Better yet, they even asked questions.
One step backward and one step forward. Certainly, there are gender disparities in blog readership (more men read blogs, particularly technical blogs), blog commenting (I’d wager than men are more likely to leave comments), twitter participation (more women tweet). This might translate into disparities of who feels comfortable attending a social networking panel. (Note: by disparities, I literally mean differences, with no judgment attached). I wonder about disparities because quite a few women asked me about the session during the conference (I received more inquiries from women than men) so I know that they were interested but didn’t show up. I don’t have a way to draw conclusions from my small sample of observations.
I’ll stop there before I put my foot in my mouth. What do you think?
Related posts:
External links:
The social networking panelists at INFORMS courtesy of Anna Nagurney
Emily Stoll from Johns Hopkins Applied Physics Laboratory gave a talk on balancing life and work as part of the Women in Math program. She offered several lessons that she has learned along the way.
Stoll has a degree in civil engineering, a degree in applied math, and an MBA. She talked about all of the different things you can do with an applied math degree. Most of her work involves homeland security applications. As a mathematical analyst, she analyzed submarine data using the Chi-squared test, Kolmogorov-Smirnov test, Fault tree analysis, and other statistical tests. She used design of experiments as well as modeling and simulation to improve port security. Her research on receiver operating (ROC) curves for IED detection was featured in the TSA’s blog.
One of the more interesting projects Stoll was involved with is the US Navy “Marine Mammals” program. She helped to optimize the location of dolphins and sea lions to interdict dangerous materials (such as mines) and for swimmer defense. Amazingly, the US Navy has been using the marine mammals program since the Vietnam War era.
All of Stoll’s work requires the use of statistics. It’s nice to know that the tools I teach students in STAT 541 (an introductory statistics course for engineers) are widely used in industry, even by mathematicians and engineers who don’t consider themselves to be statisticians.
Stoll’s excellent life lessons include:
Kim Clijsters - tennis star and mother
I was really jazzed when new mother Kim Clijsters won the US Open this weekend, the first mother to win a Grand Slam since 1980. The Guardian posted an article about work-life balance for tennis stars. They write the following:
Clijsters is far from the first sportswoman to excel after having a child – Paula Radcliffe won the New York marathon in 2007 10 months after having a child, the Kenyan runner Catherine Ndereba broke the world records at 5k and 15k in 1998 a year after giving birth, and last month, the golfer Catriona Matthew won the British Open when her second daughter was just 10 weeks old.
But success in tennis has broadly eluded mothers, a comparative paucity perhaps explained by the punishing tournament schedule that requires players to travel the globe amassing points to qualify for the major championships. [Boldface added]
This issue resonates with me. Perhaps tenure has broadly eluded mothers in academia because of conferences and networking that require academics to travel the globe in order to amass a national research reputation? Not that I am likening myself to an international tennis star, of course. I enjoy going to conferences, discussing my research, and getting new research ideas. However, I am anxious about the upcoming INFORMS Annual Meeting, since I will be away from my family for six days (four days of conference plus a day of travel on either end, since I am presenting talks in the first and last sessions of the conference and have to travel 3000 miles each way).
I’ve found that the downside to academic freedom is that it’s hard to hand off my work when I need time off. When I had my first child as a graduate student, my advisor took over while I was on unofficial leave. When I had my second child, I found it essentially impossible to hand off work (such as handling paper revisions, advising graduate students, and organizing sessions for conferences), despite receiving an excellent maternity leave. I was caught off guard by this, and in retrospect, I should have put a better system in place before baby arrived. I try not to dwell on these issues too much, because motherhood is challenging for everyone, and somehow we all manage. The little ones make the challenges worthwhile.
Link: watch an interview with Clijsters on work-life balance here.
Other athlete mothers that inspire me include Lindsey Davenport and Candace Parker (whose appearance on the cover of ESPN Magazine while pregnant resulted in a huge buzz among working mothers).
This isn’t entirely an issue for women. Last month, I read an interesting article in the Washington Post that indicates that work-life balance issues for high school football coaches ultimately keep many from taking college coaching jobs that are necessary to make the leap to the pros.
“I’ve had opportunities in the past to go to college and the main reason why I decided to stay was, years ago when I did have the opportunity, my children were young and I wasn’t sure whether I wanted to make the jump or didn’t want to make the jump,” said longtime DeMatha Coach Bill McGregor, who has compiled a 259-36-3 record during his 27 years as head coach at the Hyattsville school. “It sounds glamorous and looks glamorous and it’s better pay, but you don’t have an awful lot of security. . . . I know a lot of assistant [college] coaches right now and they’ve been at five, six, seven, eight schools. That’s a lot of uprooting and moving. I think it’s a tough life.”
What challenges do working parents in the field of operations research face?
What working parents inspire you?
Not everything is bad given the bad economy. Besides the great new trend of frugality, I have been pleasantly surprised by how many people are rethinking parenting. The idea is that we ought to think about our real objectives for our kids, and then base on parenting choices on these fundamental objectives. It’s very Value Focused Thinking, which is great. I’ve noticed a slew of articles and blog posts about Value Focused Parenting (VFP) lately.
One example of VFP I have seen lately is by Lenore Skenazy of Raising Free Range Kids. She asserts that we really want to teach kids how to be independent and make good decisions on their own. As a result, she claims that we need to gradually allow kids to have freedom and to be on their own, so they learn to make good decisions. It sounds reasonable, but she has stirred up quite the controversy. You can listen to Skenazy on a here & now interview and Manic Mommies (plus post with links). The New York Times Motherlode blog recommends several books that aim right at the heart of the VFP approach.
Related entry on value focused parenting.
In addition to VFP, morality in general seems to be trendy. Even technical blogs are writing about it (John Cook of The Endeavor wrote about the 7 deadly sins and The Dwaffler blog wrote about forgiveness)
Do you use a VFP approach? What do you think of VFP?
Punk Rock Operations Research 