Tag Archives: camberville

Analysis: Sexual Assault


On Sexual Assault in the Greater Boston Area

While homicide is an issue, it is a much smaller problem (statistically speaking) than rape. I will be talking about forcible rape, as defined by the FBI.

In 2012 the FBI changed their definition of rape for UCR.

The old definition was “The carnal knowledge of a female forcibly and against her will.”

Many agencies interpreted this definition as excluding a long list of sex offenses that are criminal in most jurisdictions, such as offenses involving oral or anal penetration, penetration with objects, and rapes of males.

The new Summary definition of Rape is: “Penetration, no matter how slight, of the vagina or anus with any body part or object, or oral penetration by a sex organ of another person, without the consent of the victim.” (Text from a 2014 FAQ released by the FBI)

Numbers from 2012 onward reflect a different definition of what [forcible] rape is–legally speaking.


CIUS and Disaster Center both use the term “forcible rape” in their reporting. Both groups showed increases in total reported cases–though by hundreds in the case of CIUS and a thousand in the case of Disaster Center.

Rapes – National 2011-2013

 Source year population total rate
CIUS 2011 311,587,816 84,175 27.00
Disaster Center 2011 311,587,816 84,175 27.00
CIUS 2012 313,914,040 84,376 26.90
Disaster Center 2012 313,873,685 85,141 27.10
CIUS 2013 316,128,839 79,770 25.20
Disaster Center 2013 316,128,839 79,770 25.20


CIUS local data only includes certain urban areas. Please note the population total for those rows.

MA – Estimates Based on National Averages

 Source year population total rate
CIUS* 2011 4,578,146 1,236.10 27.00
Disaster Center 2011 6,607,003 1,783.89 27.00
CIUS* 2012 4,629,025 1,249.84 26.90
Disaster Center 2012 6,645,303 1,794.23 27.10
CIUS* 2013 4,679,143 1,263.37 25.20
Disaster Center 2013 6,692,824 1,807.06 25.20

*Includes Boston-Quincy, MA; Cambridge-Newton-Framingham, MA; and Peabody, MA and Rockingham County-Strafford County, NH

MA – Actual

 Source year population total rate
CIUS* 2011 4,578,146 992 22.40
Disaster Center 2011 6,607,003 1,654 25.00
CIUS* 2012 4,679,143 1,286 22.40
Disaster Center 2012 6,645,303 1,650 24.80
CIUS* 2013 4,629,025 1,010 28.00
Disaster Center 2013 6,692,824 2,089 31.20

Since CIUS data is reported, there is incomplete reporting. The numbers above reflect 96.6%, 98.6%, and 95% of agencies reporting (respectively). The CIUS numbers and the DC ones are for different sized populations, with the regions of one being a subset of the other. There was a marked increase between 2012 and 2013 in the state of MA. Reporting for the newer, more liberal definition of rape was first recorded (fully) in 2013.

For city specific data, I also got numbers from City Data, which used a different term, so I included a column to specify. I could not think of a good way to organize this table. It would probably make a nicer graph.

Boston, Cambridge, Somerville – Actual

 Source year population total rate term used
Boston – CRU 2010 N/A 256 N/A rape
Boston – City Data 2011 621,359 271 43.6 rape
Boston – CIUS 2011 621,359 271 43.6 forcible rape
Boston – City Data 2012 636,479 249 39.5 rape
Boston – CIUS 2012 630,648 112 17.6 forcible rape
Boston – CIUS 2013 N/A 138 N/A forcible rape
Cambridge – CRU 2010 N/A 16 N/A rape
Cambridge – City Data 2011 105,803 24 22.7 rape
Cambridge – CIUS 2011 105,803 24 22.7 forcible rape
Cambridge – City Data 2012 106,471 20 18.7 rape
Cambridge – CIUS 2012 106,981 10 9.3 forcible rape
Cambridge – CIUS 2013 N/A 8 N/A forcible rape
Somerville – CRU 2010 N/A 13 N/A rape
Somerville – City Data 2011 N/A 17 22.3 rape
Somerville – City Data 2012 77,104 23 29.8 rape


These are just forcible rapes (as defined above) reported to the police who then, in turn, report them to the FBI. Common practice says that this only scratches the surface of sexual assault as it exists around the nation.

I really need to figure out good ways to make graphs for these posts. I think some graphs would be nice.

If you’re still looking for a New Years resolution, I would recommend that you don’t rape anyone in 2015, and encourage people who have been raped to report it.


CIUS – National

CIUS – MA 2011, 2012, 2013

Disaster Center – National

Disaster Center – MA

City Data – BostonCity Data – Cambridge

City Data – Somerville

Uniform Crime Reporting

analysis: homicide

On Homicide in the Greater Boston Area

I know someone who doesn’t feel safe taking public transit or walking alone at night. I feel perfectly safe doing these things and, generally, prefer them over cabs. Maybe I lack the visceral fear some people develop as a result of being catcalled within the city. Maybe I grew up in a (more) dangerous place, and am left generally unfazed by suburban feel of Camberville. Regardless of the reason, I don’t worry about being spontaneously raped, mugged, or shot while out.

This is about homicide.

Homicide refers to the killing of a human–as manslaughter or murder. It also includes “justifiable killings.” The FBI only includes non-negligent killings and murder.


National rates are gathered from CIUS (Crime in the US, link below), which is maintained by the FBI, and the Disaster Center. The CIUS national numbers are from 2011 and 2012, the CIUS state numbers are from 2012 and 2013. Disaster Center numbers are from 2012 and 2013.

Homicide – National

Source Years Population per 100k total
CIUS 2011 311,587,816 4.7 14,661
CIUS 2012 313,914,040 4.7 14,827
Disaster Center 2012 313,873,685 4.7 14,752
Disaster Center 2013 316,128,839 4.5 14,196


For these numbers, I took the national rate per 100k (homicides per 100k people), and estimated based on the population [(population/100,000)*homicides per 100k] The CIUS number comes from only urban areas within MA. The Disaster Center numbers are from the entire state.

MA – Estimates Based on National Averages

Source Years Population per 100k total (estimated)
CIUS* 2012 1,183,933 4.7 55.64
CIUS* 2013 1,192,220 4.7 56.03
Disaster Center 2012 6,645,303 4.7 312.33
Disaster Center 2013 6,692,824 4.5 301.18

MA – Actual

Source Years Population per 100k total
CIUS* 2012 1,183,933 3.04** 36
CIUS* 2013 1,192,220 3.61** 43^
Disaster Center 2012 6,645,303 1.82** 121
Disaster Center 2013 6,692,824 2.05** 137

*Urban areas include Boston, Cambridge, Lowell, Springfield, and Worcester

**Maths done by me. For generating the per 100k, when the number was [(population/total homicides)*100,000].

^Four of these (9.3%) are related to the Boston Marathon Bombings.

We’re doing pretty well compared to the national average.

Local Numbers

These are about Boston, Cambridge, and Somverille. There are gaps. I left open the population totals (when they were not listed on the corresponding website) because I don’t know where they got their numbers from and, as you can see, their other numbers differ.

Boston, Cambridge, Somerville – Estimates Assuming National Rates

Source Years Population per 100k total
City Data – Boston 2011 N/A 4.7 N/A
City Data – Boston 2012 636,479 4.7 29.91
City Data – Cambridge 2011 N/A 4.7 N/A
City Data – Cambridge 2012 106,471 4.7 5.00
City Data – Somerville 2011 N/A 4.7 N/A
City Data – Somerville 2012 77,104 4.7 3.62
CIUS – Boston 2011 630,648 4.7 28.38
CIUS – Boston 2012 N/A 4.7 N/A
CIUS – Cambridge 2011 106,981 4.7 5.03
CIUS – Cambridge 2012 N/A 4.7 N/A

Boston, Cambridge, Somerville – Actual

Source Years Population per 100k total
City Data – Boston 2011 N/A 10.1 63
City Data – Boston 2012 636,479 9 57
City Data – Cambridge 2011 N/A 4.7 5
City Data – Cambridge 2012 106,471 0.9 1
City Data – Somerville 2011 N/A 0 0
City Data – Somerville 2012 77,104 0 0
CIUS – Boston 2011 630,648 3.65** 23
CIUS – Boston 2012 N/A N/A N/A
CIUS – Cambridge 2011 106,981 0.93** 1
CIUS – Cambridge 2012 N/A N/A N/A

**Maths done by me, see above.

Thoughts, Additional Table, Disclaimers, etc

City Data and CIUS have really radically different numbers. City Data does provide a disclaimer saying that their information may be neither accurate nor timely. They suggest using “at your own risk.” Comparing Disaster Center and CIUS is not really worthwhile, as they consider different populations.

It’s really sad that Boston’s crime rates are higher than Camberville’s.

The FBI’s Uniform Crime Reporting (UCR) has a program called National Incident-Based Reporting System (NIBRS) This is a very specific type of reporting system, which provides very different data than the above. Starting in 2011, data previously managed by UCR was replaced with NIBRS.

Homicides: NIBRS, UCR

Source Years Population Homicides
NIBRS 2013 316,128,839 3,465
UCR (National) 2010 308,745,538 14,748
UCR (MA) 2010 6,547,629 210
UCR (Boston) 2010 617,594 73
UCR (Cambridge) 2010 105,162 0
UCR (Somerville) 2010 75,754 0

In their pamphlet, NIBRS says that only 19% of homicides in 2013 were committed by a stranger. In terms of a random person killing me on the street, I’m not worried. In Camberville, over the past few years, there was only one stranger on stranger homicide and it was far beyond what one worries about when they think about being killed randomly.

Given infinite time and resources, it would be interesting to pull up each of the specific cases of homicide in Camberville (which is very doable).

I don’t know anything about statistics beyond folk knowledge and the things you learn in bio lab and from your statistician friends. That is to say: more than the average person on the average (i.e. non-Camberville) street, but not really a lot. My maths are based on what I know: public education and intuition. I am happy to receive criticism, advice, and corrections.

I know that there are lots of crimes other than homicides that are problems. Sexual assault is huge. Writing about homicide took me so long, I decided to shelve sexual assault until a possible future.


CIUS – National is maintained by the FBI. They use the term “murder and nonnegligent manslaughter.”


Disaster Center uses the term “murder.”

Disaster Center – National

Disaster Center – MA

City Data uses the term “murder.”

City Data – Boston

City Data – Cambridge

City Data – Somerville

Uniform Crime Reporting

analysis: rent

On Rent in Camberville

I found it a little hard to write about rent in Camberville (mostly Somerville) due to the age of the data I found readily available. Additionally, it’s a heated issue. I–and my friends–choose to live here. We pick convenience over cost. Housing is the subject on which we use our energies reserved for being upset, angry, and frustrated over things we feel we can’t do anything about.

That being said, rent here really sucks.

Boston rent is the third most expensive in the US, according to CBS. It is beaten by New York and San Francisco. The majority of residents are renters. We don’t have rent control. The average rent for an average household is over $2,000.

Renters and Owners

The majority of Cambervillans are renters. Renter occupied homes have fewer people, on average, than owner occupied homes. I joke that this is because people are misreporting how many residents a given location has, considering how many people over the age of twenty-one I know who have actual roommates.

Somerville Households (2010 Census Data from American FactFinder)

Owner Occupied Renter Occupied Totals
Housing Units 10,395 21,710 32,105
Population 24,780 48,705 73,485

Average Household Size



Cambridge Households (2010 Census Data from American FactFinder)

Owner Occupied Renter Occupied Totals
Housing Units 15,235 28,797 44,032
Population 31,880 56,180 88,060
Average Household Size 2.09 1.95


These numbers come from Wikipedia, where there is a lot of ambiguity on the data. I should probably update it, assuming census.gov’s information is more correct. I have both. Unlabeled data is from Wikipedia. All income is gross, except when noted otherwise.

Camberville Income

Somerville Cambridge
Household $46,315 $47,979
Household (2010, census.gov) $64,603 $72,225
Estimated MA Take-Home (2010, census.gov) $45,114 $49,881
Family $51,243 $59,423
Men $36,333 $43,825
Women $31,418 38,489
Per Capita $23,628 21,156
Per Capita (2010, census.gov) $33,352 $48,509

I have been told that rent “should be 30% of your [take home] income.” This seems positively insane to me. That is ridiculously high. But, whatever, someone thinks it’s a good idea. Probably someone who owns land that they rent.

By these recommendations, a Somerville household should be paying $19,381/year, or $1,615.08/month. A Cambridge household ought to be paying $21,667.5/year, or $1,805.63/month. For argument’s sake, a Somerville household is 2.25 people, and a Cambridge one 2. This works out to a Somervillian paying $718/month and a Cantabridgian paying $903/month.


I apologize for my rent numbers. They are from Zillow’s positively magnificent rent data. I apologize because they are calculated from September 2014, as opposed to whenever the census was actually taken in 2010. Here are some new assumptions:

  1. Inflation since 2010 has been 9.2%
  2. Estimated Somerville household income is now: $70,521
  3. Estimated Somerville take-home income is now: $49,246
  4. Estimated Cambridge household income is now: $78,841
  5. Estimated Cambridge take-home income is now: $54,450
  6. A typical household is 2 people.
  7. Studio apartments are occupied by a single person earning as much as a household, but ought to cost less than a one-bedroom.
  8. One-bedroom apartments are occupied by 1.5 people earning as much as a single household.
  9. Three-bedroom apartments shall be calculated as 1.5 households, and four-bedroom apartments as 2 households. (Note, many people share their homes with either roommates, housemates, partners, or children. In the case of partners (or children), this could be at a greater cost.)

Median Rental Costs as of September 2014 (Zillow.com)

Somerville (estimated) Somerville (actual) Cambridge (estimated) Cambridge (actual)
All homes $2,300 $2,550
Studio <$1,231 $1,500 <$1,361 $2,140
One-bedroom $1,231 $1,760 $1,361 $2,200
Two-bedroom $1,231 $2,200 $1,361 $2,700
Three-bedroom $1,846 $2,600 $2,041 $3,300
Four-bedroom $2,462 $3,200 $2,722 $4,200

There are some problems with my estimates. I mean, lots of problems. One obvious issue is that rent is usually less per room the more rooms there are in the house.


Tufts has 5,232 undergrads (~37% off campus) and 5,651 graduate students. MIT has 4,528 undergrads (~25% live off campus) and 6,773 graduate students. Harvard [College] has 6,722 undergrads (~3% off campus) and 3,871 graduate students.


I don’t know a lot about the actual makeup of Camberville in a “by the numbers” way. Rents in some areas are cheaper than others–by a lot. Both cities have significant populations of poor people (in each city, >10% of the population lives below the poverty line). A number of my friends are hackers, engineers, developers, etc. Glassdoor tells me that the Boston Metro average developer earns $85k/year. I know some freshman engineers who had offers for $90k+benefits. I have friends who earn $500/week teaching children. Graduate student/post-doc stipends in the area range from $8k-35k/year. Massachusetts minimum wage is $8/hour.

Possibly Interesting Things, Some of Which Inspired Me

Something Wrong With Literally Everything In Apartment.” The Onion. March 19, 2011.

Parker, Brock. “Report Warns of Rent Hikes Along Green Line Route in Somerville.” Boston.com. February 12, 2014.

Conti, Katheleen. “In Suburbs, Rents Soar As Vacancy Rates Plummet.” Boston Globe. April 24, 2014.

Kooker, Naomi. “Skyrocketing Rent Has Tenants Searching Outside the City.” Boston Globe. August 17, 2014.


Thanks to Patrick Engelman for pointing out it’s 30% of take home pay, not gross. This also led to me realizing a mistake I made in calculating expected rents. I apologize.

A note added about roommates/sharing homes with partners.

I’d like to acknowledge all my awesome statistician and economist friends who read this and gave useful feedback–leading to the edits.

analysis: love

On Dating in Camberville

There’s a This American Life has an episode, for Valentine’s Day, that opens with a Harvard educated physicist relaying a story about doing the math to figure out his dating pool in Boston.

So you start with 600,000. Which sounds great, except that half of them are guys, right? And I’m only interested in girls.

He’s wrong.

So, let’s be honest, a Harvard physics student or post-doc is probably not going to date someone who lives in Boston (population 645,000). He’s more likely to date someone in Camberville (pop. 105,000 and 75,000, respectively). He might go to Medford (pop. 56,000), where Tufts calls home. Arlington (pop. 42,800) is also a possibility (in as much, maybe less, than I would say Boston is), but I add it for the sake of being thorough.

Now, let’s talk about his claim that half of his 600k people are women. He’s wrong.

Dating Pool

M.’s Table of Wikipedia Data

City Total Population Men (per 100 women)*
Arlington 42,800 83.9
Boston 645,000 89.9
Cambridge 105,000 94.7
Medford 56,000 85.2
Somerville 75,700 93

*among people over the age of 18.

This general statistic (more women than men in the Boston area), has come up recently in conversation. Someone’s girlfriend moved to Boston. They broke up. “At least the dating scene here has to be better for her than [the Midwest].” Someone else considered that the last three men they had sex with were all from outside the area.

Because I like pushing numbers, let’s see some more. I’ve rounded to the nearest integer because you can’t date .428ths of a person.

M.’s Estimates on Number of Vaguely Age Appropriate Dating Pool For A Random Adult Assuming No One Is Married, They Do Not Mind May-December Relationships or Heterosexual Relationships

City Total population % Over 18 # of Men # of Women
Arlington 42,800 35.6 6,951 8,285
Boston 645,000 47.5 145,040 161,335
Cambridge 105,000 59.8 30,540 32,250
Medford 56,000 42.6 10,974 12,881
Somerville 75,700 58.5 21,339 22,945
Totals 924,500 N/A 214,844 237,696


Reviewing assumptions:

  • Everyone wants to partner monogamously
  • Everyone is into heterosexual relationships
  • Adultery is not an issue
  • Anyone in the 18-44 age range is acceptable
  • People are looking to partner only within the Greater Boston Area.

Based on these assumptions, 22,852 women are unable to couple. That’s approximately the population of Lincolnia, Virginia.

Exempt Parties

This doesn’t take into account things like married couples In Somerville, 32.3% of the 31,555 households (10,192) were married couples. This is where things are going to get kind of weird. Most of my friends live in shared apartments. SW and LR are married, but have two (unmarried) housemates. I also don’t know how many households are over the age of 44 (or under the age of 18).

M.’s List of Households

City Total Households % Married # of Married Households
Arlington 19,007 45.1 8,572
Boston 252,699 25.5 64,438
Cambridge 44,032 28.9 12,725
Medford 22,067 45.6 10,063
Somerville 31,555 32.3 10,161

Gallup estimates that 4.4% of adults in Massachusetts are gay. This does not take into any account how many of these people are men or women. There are people who are asexual. There seems to be a decent turnover rate in the population, due to the universities and growing startup culture, though that may just be a reflection of my social circles.

Personal Conclusions

It’s no wonder my female friends keep getting together with dudes who don’t live here.

Edit: 2,2945 > 22,945. Thanks, TR.