|
|
 |
Methodology:
"Shmutz" Subway Cleanliness Survey, 2003-2004
Background
This 2003-2004 report is intended as a follow-up to the April 1998, February 1999, January 2000, February 2001 and March 2003 NYPIRG Straphangers Campaign surveys, Subway Shmutz: Cleanliness in New York City Subway Cars. The methodology followed in this survey is identical to that used in the 2000, 2001 and 2003 reports. One adjustment to the methodology of the 1998 and 1999 surveys is noted below.
Preparation
In July 1997, August 1999 and again in September 2002, our project directors accompanied members of the New York City Transit Passenger Environment Survey (PES) staff on an in-field mock rating of some 15 cars on two subway lines. This session included clarification of New York City Transit's own rating system. We also received the actual survey form used by PES staff. PES looks at several measurements of the subway car environment, including car and seat cleanliness. Our survey is an in-depth measurement of car floor and seat cleanliness only.
Rating System
PES surveyors evaluate the cleanliness of subway car floors and seats with a four-level rating system in which a score of 1 represents the highest cleanliness rating and a score of 4 represents the lowest. The following definitions are from the New York City Transit's Passenger Environment Survey, 1st Quarter 1997 and are still in use:
| Score |
PES terminology |
PES definition |
| 1 |
None |
Basically dirt free. |
| 2 |
Light |
Occasional "ground-in" spots but generally clean. |
| 3 |
Moderate |
Dingy floor, one or two sticky dry spots. |
| 4 |
Heavy |
Heavy dirt; any opened or spilled food, hazardous (e.g. rolling bottles), or malodorous conditions, sticky wet spots, any seats unusable due to unclean conditions. |
The PES notes that "the nature of the dirt (e.g. spilled food, malodorous floor/seat condition, etc.) is also considered in addition to just the volume."*
We believe our definitions more accurately reflect the meaning behind each score:
| Score |
PES terminology |
Straphangers Campaign terminology |
| 1 |
None |
Extraordinarily Clean |
| 2 |
Light |
Clean |
| 3 |
Moderate |
Dirty |
| 4 |
Heavy |
Heavily Dirty |
In our study, we used a numbered system identical to the one listed above. However, we modified the terms to describe each rating.
Survey
Our project directors trained 44 surveyors. Between October 2, 2003 to January 14, 2004, surveyors rated exactly 100 subway cars on each of 22 lines**, similar to the size of PES samples. We did not survey the Grand Central-Times Square, Rockaway and Franklin Avenue Shuttles because of the short length of these routes. Due to similarities in route patterns, observations of the 7- and 7-diamond lines and the Q- and Q-diamond lines, were combined. Measurements were taken both on weekdays and weekends, during rush hours, and evening and overnight hours.
Analysis of Survey Data
All survey data submitted was visually inspected for error and then coded for entry into a spreadsheet format. After entering the data, we calculated both by-line and systemwide totals. The percentage of cars rated "dirty" and "heavily dirty" were combined to offer a measurement of the proportion of cars with an unacceptable level of interior dirt. Similarly, "extraordinarily clean" and "clean" rating totals were combined to reflect the proportion of subway cars with an acceptable level of dirt. Systemwide car cleanliness proportion is significant at the .05 confidence level within plus or minus 3%. By-line cleanliness levels are significant at the .05 confidence level within plus or minus 7-11%:
| Line |
Percent Clean or
Extraordinarily Clean |
Confidence Interval |
| 1 |
55% |
11% |
| 2 |
66% |
10% |
| 3 |
89% |
7% |
| 4 |
78% |
9% |
| 5 |
89% |
7% |
| 6 |
87% |
8% |
| 7 |
54% |
11% |
| A |
54% |
11% |
| B |
71% |
10% |
| C |
48% |
11% |
| D |
54% |
11% |
| E |
62% |
11% |
| F |
54% |
11% |
| G |
63% |
10% |
| J |
65% |
10% |
| L |
76% |
9% |
| M |
49% |
11% |
| N |
63% |
10% |
| Q |
66% |
10% |
| R |
69% |
10% |
| V |
71% |
10% |
| W |
65% |
10% |
| System |
66% |
3% |
Table One notes that in the period between the 2002-2003 and 2003-2004 surveys, car conditions improved significantly systemwide. By-line car conditions improved on ten lines and deteriorated on three lines. Significance of these results was established with a one-tailed Z-test at the .05 level.
Comparison with PES Survey Data
The survey's finding of improvement mirror the trend in MTA New York City Transit own Passenger Environment Surveys, which shows a modest improvement in subway car cleanliness for the most recently available period. The number of clean car floors and seats (those with no or light dirt) "measured throughout the day while in service" improved from 76% in the fourth quarter of 2002 to 83% in the fourth quarter of 2003. This is consistent with the results of previous years in which New York City Transit's surveys have rated subway cars as considerably cleaner than the campaign's surveys.
Credits
The NYPIRG Straphangers Campaign wishes to thank 44 volunteers who assisted in the survey. They are:
Toyin F. Ajasin, Theo Moore, David A. Rodriguez, Spandana Nallapati, Lawrencia Mensah, Amissa Dechabeit, Meiko Harris, Arelis Hernandez, Cassandra Glover, Ed Bagley, David Harris, Richard Thomas, Tanisha Clark, Delano Aaron, Christine Agic, Carla Sterling, Yonason Kimmel, Justin Webb, Desiree' Kelly, Melissa Phillips, Laura Prussin, Ali R. Ahmad, Katheryn Ross, Charity Carbine, Marisa Ramjohn, Delio Vasquez, Kali Nelson, Elana Dekaye, Ofelia Virtuao, Bobby Jones, Roberto Gordillo, Justin Aguinaldo, Marwa Amer, Richard Tsai, Mark Griffith, Joel Serrano, Keith Causin, Nigel Bennett, Ed Jean-Baptiste, Aisha Fraites, Alicia Graham, Antonio Cruz, Stephen Jacob and Phil Urban.
. . . . .
* Passenger Environment Survey, New York City Transit, First Quarter 1997, p. 11
** The sample size per line is identical to that used in the 2000 and 2001 surveys. In 2002, two new lines--the V and W--were included in our analysis. In 1999 and 1998 Straphangers Campaign surveyors rated approximately 100 cars on each line surveyed.
. . . . .
shmutz survey news release | methodology | chart 1: breakdown of subway car cleanliness
table 1: percentage of clean cars by line | table 2: worst to best--percentage of clean cars by line
_____________________________________________________________
www.straphangers.org | www.nypirg.org
|
|
