Husky Den Signage Analysis - The UW Garbology...
Transcript of Husky Den Signage Analysis - The UW Garbology...
Jack Johnson UW Garbology Project Final Report: Husky Den Waste Bin Signage 6/21/2013 Abstract This document summarizes a pilot study undertaken by the UW Garbology Project (UWGP) in collaboration with the UW Climate Action Plan (UW CAP) to examine which (if any) types of posted waste-‐sorting signs common to UW campus waste disposal bins are most effective in terms of encouraging waste diversion through increased recycling and composting. Project background and objectives are discussed first. This discussion is followed by a detailed description of methods, data, and resultant interpretations and conclusions. It is argued that collected data suggest an underlying difference in average waste diversion rates as a result of posted sign types, with signs produced by UW CAP ranking most effective at diverting waste, signs produced by UW Recycling ranking 2nd most effective, signs produced by UW Housing and Food Services (UW HFS) ranking 3rd most effective, and bins absent guides for sorting ranking least effective. Importantly, however, this difference between sign types is statistically modest in comparison with background variance in accumulations within bins, meaning these results should be considered provisional until further study can be performed. Finally, a short series of recommendations for such study are provided, along with a discussion of possible next steps in developing, testing, and implementing more effective signs on campus waste bins. Background Previous work by the UW Garbology Project (UWGP) has documented the composition of UW campus waste in various settings as a means of identifying key areas for improvement in UW’s ongoing efforts to divert more of our waste from ending up in landfills. Through this work it has become clear that campus users often dispose of waste incorrectly, even in cases where infrastructure is readily available for proper waste disposal. For example, we have shown that up to 88% (by mass) of items placed in landfill-‐bound trash bins are compostable or recyclable even when these trash bins are directly adjacent to recycling and compost bins1. Thus if our goal is to divert more waste from landfills – thereby improving both UW’s fiscal bottom line as well as its environmental sustainability – we clearly need to do a better job of encouraging the UW community to properly use the waste infrastructure provided for them. Such improvement could be initiated a variety of ways (and we are currently exploring a number of them), but signage placed on bins is a good place to start for a host of reasons. Foremost amongst these reasons is the fact that bin signs are, by dint of location, the visual reference upon which users are most likely to rely at the moment of discard, and as such the degree to which these signs are effective at communicating the nuances of proper disposal is likely to strongly impact how waste is discarded in aggregate. Importantly, these nuances are not trivial, as properly sorting the broad and confusing array of materials discarded on campus can be quite difficult in practice, especially for campus users who have been educated in one of the vast constellation of differing municipal systems in place elsewhere. We therefore need good signs on bins to aid users in proper sorting. Our current infrastructure recognizes this need, and sorting signs on bins are relatively common on campus, especially in indoor areas. Unfortunately, a broad array of types of signage are currently
1 http://uwgarbology.weebly.com/uploads/1/3/0/1/13017489/fall_2012_final_report_v1.1.pdf
employed, and it is not uncommon to find several distinct types of signs in close proximity. Figures 1-‐4, for example, show three different types of signs within the Husky Den alone, and the result of this inconsistency is greater complexity for the user to interpret, and therefore greater effort on the part of the user to engage in good disposal behavior. In other words, the existence of multiple sign types is likely to be sub-‐optimal in terms of user-‐friendliness, since it entails a slightly greater potential for confusion or outright disregard than a system which helps build good habits through consistent, easily-‐recognizable standardized visual references. To make matters worse, some of the signs currently in use on campus are incomplete (omitting certain items very common to campus; see Fig. 5) or downright outdated and misleading (See Fig. 6), which can only further frustrate or confuse users looking to quickly and easily discard their waste. Still needed, then, is a set of signs which is 1) accurate and up-‐to-‐date, 2) tailored to the waste items campus users are most likely to discard, and 3) implemented across campus to the exclusion (where possible) of other, competing sign types. Fortunately, many campus organizations, including UW Recycling, the UW Climate Action Plan (UW CAP), and UW Housing and Food Services (UW HFS) have designed distinct sets of signs which easily meet the first two criteria (again, see Figs. 1-‐4), and there exists a plentiful crop of candidates from which to select one to promote to campus ubiquity. In selecting one sign type to predominate, however, we should seek data which allow us to evaluate which (if any) of our current options works best. In other words, we should find a way to measure and document which type of signs actually improves waste diversion by 1) increasing rates of composting and recycling relative to landfilling and 2) reducing contamination in waste bins of all types. Objectives Simply put, the primary aim of the work detailed here was to begin to meet this need through a study of the effects of different signage upon accumulation rates in waste bins within the Husky Den (the dining area of the Husky Union Building, or HUB). Secondary goals included 1) building working relationships with UW CAP (who collaborated on the project) and UW HFS staff working in the Husky Den to form the basis for potential future collaborations, and 2) field-‐testing new methods for measuring waste accumulation rates with laser distance measurers (see below) before applying these methods to broader UWGP initiatives across campus. The Husky Den itself was chosen for several reasons. First, it is a high-‐traffic dining area which produces a high waste load which operates well above the average campus-‐wide waste diversion rate2,3, and as such it was expected to provide both a dynamic environment for sampling as well as insight into a relatively ideal portion of UW’s waste system. Second, the area contains 11 total sets of waste bins (see Fig. 7 for a map), allowing examination and comparison of a healthy sample of distinct bin locations within a single dining area. Third, this area contains 4 different signage types among its 11 waste bin locations – 3 locations display UW CAP signs, 3 display UW Recycling signs, 4 display UW HFS signs, and 1 displays no sorting signs (bins here are labeled as compost, recycling, or trash, but no guide is posted as to which items belong in which bins) – allowing a good basis for comparison between each of 3 potentially viable signage types and a control location. Lastly, upon inception of this project UW CAP
2 According to data provided by Emily Newcomer, Manager of UW Recycling, over 77 tons of waste were collected from the HUB between September 2012 and the end of January 2013. Composition of that waste was about 23.7% recyclables, 43.1% compost, and 33.2% trash, for a total diversion rate of about 66.8%. 3 UW Recycling’s FY 2012 report estimates the current campus-‐wide waste diversion rate to be about 57% (see http://www.washington.edu/facilities/building/recyclingandsolidwaste/files/report2012/index.html).
was already working within the Husky Den and could provide access and logistical support for our efforts, lowering our investment of time and resources in this endeavor. This is not to say that this space and our access to it were free of logistical challenges. In fact, the truth is quite the opposite; because this is a first-‐time collaboration, Husky Den staff members were reticent to allow us to carry out the full scope of the study we initially envisioned. Specifically, since our interest was in ascertaining the impacts of signage on bin accumulation rates and contamination, we were interested in performing 1) spot checks of bin accumulations, 2) measurements of bulk weights of waste produced at bin locations, and 3) sorting and analysis of subsamples of waste, but Husky Den staff preferred we limit our initial investigation to only the first of these dimensions until we were able to demonstrate that we were trustworthy, productive, and unobtrusive collaborators. This is a perfectly fair stance on their part, but it meant limitations in data collection for this study. As such, our objectives have been tempered by the type of data we could reasonably generate. Specifically, we were unable to calculate waste diversion in terms of mass (as is the norm) and we had to jettison an investigation of contamination, as we were only able to collect data relevant to how quickly waste volume of different types accumulates as a function of posted signage. Still, this limited objective is informative and worthwhile as a basis for both initial interpretation and future investigation, even if it results in conclusions which are neither comprehensive nor definitive. Methods Given the above objectives and considerations, the methods employed in this project were generally aimed at enabling comparison of diversion rates associated with distinct sign types without the need for either 1) weighing any waste or 2) withdrawing any samples of waste from bins. As such, the methods used here hinged entirely on the use of volumetric estimates of waste accumulation rates within bins as a basis of comparison. Because all waste bins in the Husky Den are identical in their internal spatial dimensions, we were able to use simple bin “fullness” as a proxy for the amount of accumulation within each individual bin. Fullness was measured with the use of a Bosch DLE 40 laser distance measurer (LDM) by holding the LDM in such a way that its optics were even with the horizontal plane at the bin aperture, its optics were centered within the bin aperture in plan view, and its beam emitted perpendicular to the horizontal plane. In other words, we held the device so that it measured the distance from the top of each bin straight down into the center of the waste accumulated in the bin itself. This allowed us to quickly and cleanly measure the surface heights of accumulated waste in a consistent and standardized way, in turn aiding the collection of abundant data which would be directly comparable between bin measurements. Measurements of bin fullness were repeated for each bin at all 11 Husky Den bin locations between 2 and 3 times daily every Monday through Friday for a period of 5 weeks during spring quarter 2013. Each measurement of bin fullness was accompanied by a notation of time, bin type, sign type, and bin location, allowing data to be segmented by these dimensions and normalized by elapsed interval. Measurements were conducted at roughly 9:00 AM, 11:30 AM, and 1:30 PM; these times allowed us to work around volunteer availability while capturing accumulation rates during peak use hours (lunchtime) in the Husky Den in the face of rolling bin-‐emptying episodes (Husky Den custodians empty bins as needed rather than on a set schedule). The resultant dataset provided a set of time-‐lapse snapshots of accumulations within all Husky Den bins over a roughly 4.5 hour period for a total of 25 days. This dataset is not reported in full here for purposes of brevity.
When measurement finished, this dataset was used to derive relative volumetric diversion rates for each of the 11 bin locations. This was done by first removing data in cases where negative bin accumulations were observed for an interval, as these instances represent bin-‐emptying episodes and therefore cannot provide reliable indices of accumulation rates. After these data were removed from consideration, accumulation rates for each bin at each location were derived and expressed as meters per hour to normalize all bin measurements within each interval. This was necessary to correct for variance in apparent bin accumulations as a product of the ~10-‐15 minutes needed to complete each measurement episode. Accumulation rates were then ranked for each bin type and each interval. This step was necessary for two primary reasons. First, it allowed data from different temporal intervals to be collapsed into a common basis of comparison; if this hadn’t been done, results from the early (9:00-‐11:30) interval would not have been directly comparable with those of the later (11:30-‐1:30) interval due to the fact that the later interval witnessed much more rapid accumulations of waste, thereby rendering it a different waste system (in a statistical sense) at the ratio scale of measurement. Second, it allowed us to minimize the effects of any inaccuracies incurred by using single-‐point fullness measurements to represent waste surfaces of uneven topography. In sum, then, using rank-‐order data rather than ratio scale data allowed us to boost sample size by making full use of all measurements while helping to ensure data and conclusions were relatively robust to individual measurement errors. Once these rankings were derived, they were then pooled by location and averaged for each bin type to yield average ranks of each location’s accumulation rates within each bin type. In other words, we were at this stage able to determine which location typically exhibited the highest (and 2nd highest, 3rd highest, etc.) accumulation of compost, recyclables, and/or landfilled trash. This was repeated for data pooled by signage type rather than by location alone. These average rankings are provided in Tables 1 (by signage type) and 2 (by bin location). Taken alone, each of these rankings means little in terms of waste diversion, since they could in part be driven by raw accumulation rates as a result of location; one bin set might rank highly in all areas simply because it’s next to a major vendor, seating area, or exit, for example. From these rankings, however, average differences in rank between trash and compost (T-‐C scores) and between trash and recyclables (T-‐R scores) were derived for each location and signage type; these scores are a more useful measure of relative diversion rates, as they highlight which bins within a given location/signage type accumulate waste more rapidly than other bins with the same location/sign type. In other words, these scores indicate the degree to which accumulation associated with a given signage type or location was on average dominated by trash (negative scores) or by recycling/compost (positive scores) compared to other signage types/locations, and as such these scores may stand as a proxy for relative volumetric waste diversion. Discussion of Results Upon consideration of the data in Table 1, it is clear that all signage types are on average fairly similar in their performance, as all signage types exhibit moderate average rankings of between 5.3 and 6.1 for all bin types. If signage type were strongly and consistently affecting waste deposition outcomes, average rankings would exhibit a greater range of values and standard deviations in average rankings would be lower on the whole, reflecting greater convergence on a pattern of clear difference in performance. As it stands, differences in performance between signage types are not statistically significant, indicating that any differences among the signage types examined are not a primary determining factor in how waste is categorized upon disposal in the Husky Den. Instead, random or external factors – such as individuals’ inherent preconceptions and/or biases – currently seem to be the predominant forces shaping how waste is discarded at a given location.
Still, some moderate differences in signage performance are likely affecting bin accumulations, as some sign types are on average ranked slightly higher than others in terms of compost and recyclables accumulated relative to trash accumulated. UW CAP signs, for example, were associated with the lowest average accumulations of trash and the highest average accumulations of recyclables. This same set of signs was also on average more highly ranked in its compost accumulations than in its accumulations of trash, and taken together these facts indicate that the overall waste stream moving through locations displaying UW CAP signs is slightly more weighted towards recyclables and compost (and therefore more weighted away from trash) than locations displaying other sign types. Locations displaying UW Recycling signs did almost as well as UW CAP signs in terms of producing overall waste streams which were more weighted towards recycling and compost. UW HFS signs performed relatively poorly overall, as they were associated with a waste stream that was on average ranked more highly in trash accumulations than in accumulations of either compost or recycling. The lone location without signs to aid in sorting produced the waste stream that was most strongly associated with more trash and less compost or recycling (exhibiting T-‐R|C scores (see Tables 1 and 2) which average a full rank lower than UW CAP signs), although just barely, as UW HFS signs performed only a hair’s breadth better. Again, these results are not statistically significant, but they are suggestive that some of these signs “worked” slightly better than others over the 25 days studied, and as such they represent potentially fertile ground for future investigation, perhaps under more controlled experimental conditions in which true ratio-‐scale comparisons are possible, sample sizes are larger, masses of accumulations can be measured, and/or statistical variance associated with estimates can be otherwise minimized. By contrast to patterns in signage type, higher average rankings of compost and recyclables relative to trash do not exhibit an apparent spatial pattern (see Fig 8). In fact, in some cases (for example, bin locations 1 and 4 and bin locations 8 and 9) bin locations exhibiting markedly different T-‐R|C scores sit immediately adjacent to one another within the same Husky Den enclosure; geography therefore clearly plays no role in differences between these bins. Consequently, the present evidence suggests that – as far as diversion rates are concerned – proximity to a certain vendor, exit, or seating area within the Husky Den is a non-‐factor compared to signage type4. Since geography and signage type are the only dimensions in which these bins differ in terms of user experience, the (provisional, at present) elimination of geography as a causal factor in waste diversion strengthens the assertion that observed differences between diversion rates (to the extent they are evident) are probably due to differences in signage type alone. In sum, then, the results of this study are encouraging. While there is room for improvement upon our methods and findings, the results are generally consistent with the assertion that good signage plays some role in aiding waste diversion, even in a sampling environment already operating well above average campus-‐wide waste diversion rates, and that this role is greater than that played by bin location. Given the exploratory nature of the project, we therefore count this work as a success, and hope it will form the foundation of future efforts to investigate the role of signage further.
4 This supposition could be further tested, of course, by rotating signage to different locations to determine whether accumulations are altered according to signage or remain tied to location itself; such an experiment would be worthwhile in any case, as results could amplify observed patterns, obscure these patterns, or illuminate new patterns altogether.
Recommendations While the preceding discussion leaves room for some interpretation and debate in terms of the strength of observed patterns, for the present these patterns are at least consistent enough that we are in a position to make recommendations moving forward. These recommendations are detailed below. Recommendation 1: Repeat the experiment under more controlled conditions. It may ultimately be the case that signage type matters little compared to other factors affecting waste diversion, and as such it may be the case that even the most controlled study will fail to produce statistically significant differences between the performance of different signage types. On the other hand, we have not yet achieved the experimental control needed to support this hypothetical. It would therefore be premature to presume we can’t do better next time, particularly because over the course of this pilot study our challenges included: 1) an inability to control custodians’ waste collection times, leading to discarded observations and extra variance in data, and therefore extra error terms in results, 2) an inability to sort waste, constraining our ability to either a) translate volumetric estimates into either mass estimates, or b) evaluate contamination, and 3) an inability to implement a mid-‐study movement of sign types to other bin locations – say, swapping UW CAP signs with UW HFS signs – as a means of testing whether patterns in accumulations follow signage type or remain tied to a set location. Given these difficulties, our ability to discern even marginal differences between signage types is a promising achievement, and likely merits a future study which addresses these unmet needs by: 1) working with custodians to coordinate a set daily interval for measurement, to be preceded by the universal emptying of all bins so that a common baseline for accumulations is achieved, 2) combining spot-‐checks with sub-‐sampling for sorting and weighing, 3) moving signs to other bin locations mid-‐study, and 4) conducting measurements over a much larger sample of days, allowing better characterization of variance and therefore (potentially) lowering error terms, as well as facilitating sign-‐swapping mid-‐study. This strategy will obviously require more work (sorting, longer study duration), greater collaboration with Husky Den staff (implementing coordinated emptying and sampling), and more infrastructure (facilities and supplies for collection and sorting), but it would carry the benefit of a more limited daily engagement on the part of volunteers (spot-‐checks would only need to be performed once daily, at the end of the designated interval) as well as more definitive results. The UW Garbology Project has the resources to accommodate these needs in terms of labor, facilities, and supplies; all that remains is to procure slightly greater access and collaboration with Husky Den management and custodial staff. Given the potential benefits of this work in terms of increased waste diversion, we think pushing to procure this access and collaboration is a worthwhile endeavor. Recommendation 2: Expand the scope of inquiry to incorporate qualitative data. Everything we have done so far explores whether signage type makes a difference in terms of waste accumulations. Missing, however, is any investigation as to why one particular type of sign might perform better than another in practice. Does one sign type grab attention better than others, making users more likely to use it as a reference? Does one sign type communicate sorting criteria more effectively than others, aiding users (once engaged) to more easily make better sorting decisions? Addressing these dimensions will be critical to efficiently refining our signage moving forward, since it will allow the deliberate creation and implementation of signage with attributes known to be effective. In broad terms, such systematic investigation must begin by hypothesizing which particular factors enhance one sign’s communicative power over another – for example, perhaps UW HFS signs perform worse because the text on them is small and hard to read – but ultimately these hypotheses will need to be tested with evidence if concrete progress is to be made. Because this testing process will ultimately
involve waste analysis (the only relevant endpoint when waste diversion is the goal) it will be relatively resource-‐intensive compared to the process of generating hypotheses, thereby placing a premium on the generation of good hypotheses at the outset. In other words, in investigating why some signs work better than others it will pay to prioritize testing of only those hypothesized factors which are most likely to matter to users. A smart way to engage the process of hypothesis generation would therefore be to begin by basing hypotheses on qualitative observations derived from actual users of UW’s waste infrastructure. Controlled surveys or interviews with users would, for example, serve to highlight how users interact with signs of different types, and might provide fertile ground for identifying which (if any) attributes of signs might lead to greater effectiveness. Targeted testing of these attributes could then proceed based on these insights, accelerating the process of refining the effectiveness of our signage. None of this is novel, of course – market research firms have been conducting focus groups for decades – but its systematic application to effective waste diversion has yet to reach its potential. Recommendation 3: In the meantime, use UW CAP signs where/when it makes sense to do so. Use UW Recycling signs in other locations. Statistical caveats notwithstanding, we cannot ignore the facts that 1) the results of this study derive from an extensive dataset (50 measurement intervals; 25 days, 2 intervals per day), and are therefore substantial, and 2) these results suggest that UW CAP signage performs better on average than any of the tested alternatives. At present, we are not in a position to turn a blind eye to strategies which enjoy some empirical support for improved waste diversion – improvement to our campus-‐wide waste diversion rates has slowed considerably over the last few years5 and these rates remain far from UW Recycling’s year 2020 goals6 – if our only alternative is to simply wait idly for something better to come along. Instead, we should press any potential improvement at our disposal, especially those that incur implementation costs which are essentially negligible. As such, until fully conclusive data are available, the prudent course of action is to implement UW CAP signs where practical. Because their material composition means that these signs cannot be mass-‐produced and will really only function in indoor locations, “practical” at present means that these signs should only be implemented in high-‐traffic areas (like campus cafes) if/when other signage types are absent or already in the process of being replaced. If this is done, small average improvements in waste diversion could result in multiple tons’ worth of additional waste diversion each year in these limited contexts alone. Additionally, UW Recycling signs, which also perform reasonably well in terms of encouraging waste diversion, are weatherproof and can be cheaply mass-‐produced. These signs therefore can and should be implemented far and wide in the short term. In particular, these signs should replace the range of outdated or misleading signs scattered across campus. Given the results of this pilot study, it would likely benefit campus waste diversion efforts if these signs were to broadly replace UW HFS signs as well. Acknowledgements Thanks are due to UW CAP staff members Elise Glassman and Steve Smith for collaborating on all stages of this project, Husky Den staff for allowing implementation of UW CAP signs for purposes of this study,
5 http://www.washington.edu/facilities/building/recyclingandsolidwaste/files/2011Report.pdf 6 UW Recycling aims for 70% waste diversion by 2020.
and to the long list of volunteers who performed daily measurements, including Elise and Steve as well as Johnny Cheng, Megan Rue, Amy Mandin, Angela Battle, Claudia Frere, Melanie Wade, and Adam Fahlstrom. Figures and Tables
Figure 1: An example of UW Recycling bin signage on Husky Den waste bins.
Figure 2: An example of UW Housing and Food Services (HFS) bin signage on Husky Den waste bins.
Figure 3: An example of UW Climate Action Plan (CAP) bin signage on Husky Den waste bins.
Figure 4: Close-‐up examples of each type of compost sign on display in the Husky Den. From left to right: UW
Recycling sign, UW HFS sign, UW CAP sign.
Figure 5: A sign on a campus compost bin. This sign makes no mention of compostable plastics whatsoever,
leaving user to categorize their plastics on their own.
Figure 6: Another sign on a different campus compost bin. The sign prohibits plastic take-‐out containers and utensils even though all plastic utensils and take-‐out containers sold on campus are now compostable at Cedar
Grove.
Figure 7: A map of Husky Den waste bin locations. Bins 3, 6, and 9 displayed UW CAP (CAP) signs. Bins 1, 2, and 5 displayed UW Recycling (UWR) signs. Bins 4, 8, 10, and 11 displayed UW HFS (HFS) signs. Bin 7 had no guides for
materials sorting (N/A) on display. This map is modified from an image provided by Steve Smith (UW CAP).
Sign Type Average Rank Standard Deviation in Rank Diff. in Average Rank
Trash Recycling Compost Trash Recycling Compost T -‐ R T -‐ C (T-‐R|C)
UW CAP 6.1 5.3 5.8 2.9 2.8 2.8 0.8 0.3 0.6 UW Recycling 6.0 5.6 5.7 3.1 2.8 2.5 0.4 0.3 0.4 UW HFS 5.3 5.7 5.3 2.6 2.6 3.0 -‐0.5 0.0 -‐0.2
None 5.4 5.6 5.8 2.7 2.8 2.5 -‐0.2 -‐0.4 -‐0.3 Table 1: Results of analysis, displayed by signage type. Shown are average ranks of accumulation rates for each
bin type (left) and standard deviations in these averages (center). Higher numbers indicate lower-‐ranked bins, and therefore lower average accumulations. At right differences between average ranks of accumulations of trash and
those of recyclables (T-‐R) and compost (T-‐C) are shown; more positive numbers indicate higher rates of composting and recycling compared to discard in landfill-‐bound trash bins, while more negative numbers
represent higher rates of discard in landfill trash bins relative to composting and recycling. T-‐R|C represents the average of T-‐R and T-‐C scores, and provides a quick summary of a sign type’s relative overall waste diversion rate.
Location Average Rank Standard Deviation in Rank Difference in Average Rank
Trash Recycling Compost Trash Recycling Compost T -‐ R T -‐ C T-‐R|C
1 5.3 5.3 5.6 3.4 3.0 2.7 -‐0.1 -‐0.3 -‐0.2 2 8.0 6.5 6.2 1.9 2.6 2.0 1.5 1.8 1.7 3 7.0 6.2 6.2 2.3 2.5 2.8 0.8 0.8 0.8 4 5.9 5.4 5.3 2.6 2.6 2.9 0.5 0.7 0.6 5 4.7 4.8 5.4 2.9 2.5 2.9 -‐0.1 -‐0.7 -‐0.4 6 5.4 4.8 6.0 3.2 3.1 3.0 0.7 -‐0.5 0.1 7 5.4 5.6 5.8 2.7 2.8 2.5 -‐0.2 -‐0.4 -‐0.3 8 4.5 4.4 4.7 2.5 2.3 3.6 0.1 -‐0.2 -‐0.1 9 5.9 4.9 5.4 2.9 2.8 2.8 1.0 0.6 0.8
10 4.4 6.0 4.8 2.2 2.5 2.6 -‐1.6 -‐0.3 -‐1.0 11 6.2 7.1 6.3 2.7 2.5 2.5 -‐0.9 -‐0.1 -‐0.5
Table 2: Results of analysis, displayed by bin location. Shown are average ranks of accumulation rates for each bin type (left) and standard deviations in these averages (center). Higher numbers indicate lower-‐ranked bins, and
therefore lower average accumulations. At right differences between average ranks of accumulations of trash and those of recyclables (T-‐R) and compost (T-‐C) are shown; more positive numbers indicate higher rates of composting and recycling compared to discard in landfill-‐bound trash bins, while more negative numbers
represent higher rates of discard in landfill trash bins relative to composting and recycling. T-‐R|C represents the average of T-‐R and T-‐C scores, and provides a quick summary of a location’s relative overall waste diversion rate.
Figure 8: A map of Husky Den waste bin locations showing T-‐R|C scores for each location (the far right column of Tables 1 and 2). Importantly, high and/or low values are not strongly associated with any given region, implying location within the Husky Den is not a primary influence on the way users categorize waste upon deposition. This
map is modified from an image provided by Steve Smith (UW CAP).