1. Baseline Data (Before construction)

• With any evaluation, one of the core questions you want to answer is, “Compared to what?”

• Collect baseline data before project construction starts, so when you measure benefits after construction, you have a ‘starting line’ against which you can compare your new data.

2. Short-Term Benefits (six months after construction)

• While some benefits will not be seen until a year or more after construction, it’s important to measure initial signs of progress closer to your project’s completion so you can determine whether the GI project remains on track to generate the full results you seek.

• For example, you may have ambitious goals for how your project will improve social cohesion and physical health in your community. If you measure progress at six months post-construction, your data may tell you that you need to boost messaging within your community around the project, so it is used more often.

• To be resource-conscious, pick a few key benefits that are most important to you and the community to measure, since you will be conducting a more comprehensive round of measurement at 12 months post-construction.

3. Long-Term Benefits (12 months after construction)

• At one-year post-construction, many of your project’s benefits will be more pronounced compared to those at the six-month mark, from water and air improvements, to health and social improvements.

• Compared to six-month measurement, your 12-month data collection will be more extensive, thus taking more time and resources to complete.

4. Longitudinal Measurement (annually from 2-5 years after construction)

• Focus on the few priority-benefits you collected data on at the baseline and 6-month stages. Measure continued progress at the two-year mark and beyond.

• Be as consistent as possible regarding the weather and the time of year when collecting measurements. In most areas of the country, park use will decline in winter and pick up in the spring and summer, so keep timing in mind when measuring benefits.

*NRPA uses the term “correlated” rather than “caused by,” because outside of pharmaceutical trials and laboratory research, it is nearly impossible to claim that an impact was directly caused by an intervention.

If your organization has the resources to perform a Model 3 evaluation, NRPA recommends partnering with a third-party firm that has experience running complex, longitudinal evaluations at sites similar to your project site. Connect with researchers from your local university in the public health, environmental science, and/or urban planning departments or with a private evaluation consulting firm.

The ability of GI projects to divert and treat stormwater, reduce flooding and improve water quality remain the most basic and fundamental benefits.

Of all the benefits, it will likely be measured by your construction contractor and/or your local government. Even if others are measuring on your behalf, it still is important to know how this information is collected.

Collection Method #1: Stormwater Runoff Calculations
Calculate your project's impact on stormwater runoff using the Modified Rational Method using a Rational Method Calculator. The Rational Method estimates peak stormwater runoff volume from rain events, and it provides a useful formula for measuring your project’s potential impact on flooding reduction.

Collection Method #2: Photography on the Ground
Use photography to support data from stormwater runoff calculations. Photography is a powerful, and methodologically sound way to document the following:

• Flooding reductions immediately after rain events vs. pre-GI construction

• Changes to greenspace in and around the project area

• Use of the GI feature by the public (if applicable)

For photography to be useful for evaluation purposes, you must:

• Focus your photos specifically on impacts you will be assessing over time

• Take numerous photos (a) before project construction, in normal and inclement weather, and (b) after project construction, in similar conditions

• Collect data in identical conditions whenever possible — similar temperature, season, time of day, angle of photograph, etc.

• Drones are becoming a common tool to capture changes in tree canopy, which could be relevant depending on your project

Collection Method: Citizen Science “BioBlitzes”

The U.S. Environmental Protection Agency (EPA) defines Citizen Science as “the involvement of the public in scientific research.” Nonscientist civilian volunteers partner with members of the scientific community to collect data within the parameters of a specific project. When done properly, these partnerships provide valuable outlets for civic engagement in the sciences, and serve as a resource-conscious method for collecting data and observations to inform environmental investigations.

“BioBlitzes” are community-driven events, organized by you (or other park agency professionals), to collect flora and fauna data in the park around your new GI feature. You also can use Citizen Science to gather water and air quality data, although that kind of data collection requires citizens with a greater amount of scientific training and experience.

See the BioBlitz Guide in the downloads of this Framework, which guides you through every step of a successful BioBlitz.

Collection Method: iTree 
iTree, is a software suite developed and released by the U.S. Forest Service in 2006. It allows you to calculate a wide variety of urban and rural forest-related data tied to your GI project including:

• Air pollution reduction
• Carbon capture
• Tree canopy differences
• Impacts on water flow and quality

iTree has over 10 different applications for assessing tree/greenspace benefits to communities. Start with iTree Eco. After inputting basic data regarding species, scope and other key project information, you will be able to download a variety of benefits-related data.

Collection Methods:

• System for Observing Play and Recreation in Communities (SOPARC)
• Community Park Audit Tool (CPAT)
• Accelerometers
• Hospital records

There are many facets in measuring differences in physical health brought by your GI project. You should consider measures related to not only community members' physical activity levels, but also how your GI project encourages accessto physical activity, so that you understand how the project has influenced the park’s infrastructure. The table below outlines five potential areas for collection, along with web links to further explore the areas:

Mental Health Data Collection: Survey Instruments 
Mental health measurement — which focuses on stress and anxiety relief in this Framework — is highly qualitative and perception-based, making surveys the ideal method for collecting this data. Find two survey instruments described below. If you decide to incorporate surveys into your measurement plan, see the surveying tips and techniques in Step 2 of this Framework.

RAND Park Use Survey

• Background: The survey comes from a 2006 Los Angeles-based study on how public parks influence the physical and mental health of community members. The study was a part of RAND’s larger Population Health and Health Disparities project, funded by NIH.

• Questions: The survey, though not explicitly designed around GI benefits, connects strongly to several physical, mental and social GI project benefits covered in this Framework, including, but not limited to, questions about exercise, stress levels and public safety.

• Pros: The tested instrument supplies many questions that cover a diverse array of GI benefits. It also includes a companion survey aimed at parents with children, which could be useful if your GI project identifies children as an intended beneficiary.

• Cons: The lengthy survey covers so much ground that not all questions will be relevant to the benefits/goals of your GI project.

NRPA Community Survey Tool

• Background: Since summer 2018, cities around the country have been administering the survey; it is part of NRPA’s Great Urban Parks Campaign, focused on spreading GI best practices nationally.

• Questions: The survey focuses on respondent perceptions across many benefits discussed in this Framework, from stress relief and physical activity levels, to public safety and community cohesion.

• Pros: A brief survey, intentionally was designed for a three-minute public intercept interview. Like the RAND survey, it covers a wide range of GI benefit areas, though on a more limited level.

• Cons: Because the survey is so brief, data obtained will not be as rich and extensive as it would be if you used the RAND survey. And unlike the RAND survey, this instrument has not yet been tested and validated in a formal study setting.

Collection Method: Center for Active Design’s ACES survey

• The Center for Active Design, a New York City design nonprofit, focuses on how the built environment can contribute to a community’s physical, mental and social health.

• As mentioned in Step 1, this Framework’s definition of Social Cohesion comes in part from the Center for Active Design’s ASSEMBLY Civic Engagement work.

• The Center administered their ASSEMBLY Civic Design Survey (ACES) survey nationally to inform design recommendations for city planners, real estate developers and others in the design arena.

• While this survey is not GI-specific, questions in three survey categories strongly relate to how GI impacts a community’s social cohesion. Below find a few relevant questions to consider asking:

Public Safety
Collection Method: Local Crime Data Analysis

• LexisNexis provides a user-friendly crime mapping tool, Community Crime Map, that allows searches of local crime results by type of offense, date and location.

• If you don’t see your community included in this tool — to ensure the accuracy of your LexisNexis data pull — consult your local police department for neighborhood crime records in and around your project site to confirm your analysis.

• Numerous factors can lead to reduced crime, so you will want to look at similar data for control sites. You should also minimize your search area, as the reductions likely will be localized within a mile or so from your project.

Community Activation
Collection Method #1: U.S. Census Data Accessed Through GIS software

• To measure your project’s reach into the community, first calculate the number of people nearby who have access to your project, especially if the GI feature(s) involved have a community engagement component (e.g., trail enhancements).

• If your organization owns GIS software, you can enter your project’s address and easily pull reports on how many community members live within a 10, 20 or 30 minute walk from your project (and you can do the same for driving time).

• ArcGIS pulls in a wide variety of data points taken directly from 2010 U.S. Census data including the American Community Survey as well as other sources showing demographic and income data from the neighborhood(s) surrounding your project.

Collection Method #2: Your Project Records 

• Simple record keeping can help you track how and when you engaged your community throughout the entire cycle of the project.

• Make note of relationships that you built to see the project to fruition (neighborhood associations, school officials, nonprofit and/or private sector partners, etc.)

• If you involved a core group of stakeholders throughout the project, hold brief, informal discussions every couple of months to update them on how you are engaging local entities in the work before, during and after construction.

• Ask at least one question on the Community Survey Tool’s post-construction survey about whether respondents feel they were properly aware of, and engaged with, the project throughout its lifecycle.

Collection Method #3: NRPA’s Community Survey Tool

• NRPA’s Community Survey Tool offers an easy way to measure your project’s contribution to enhancing the community’s knowledge and use of GI.

• Awareness, knowledge and use of GI ensures that green infrastructure practices are spreading and taking hold in the larger community.

• Refer back to the Health Data Collection section to read more about the Community Survey Tool.

Collection Method: Project Records

• Track the immediate economic benefits of your project through your organization’s records: how many community residents were employed or volunteered throughout the installation of the GI project?

• How much money did your agency or your contractor spend within the community for construction supplies and any other expenses?

• Tally your total dollar amount; you may be surprised by the cumulative impact on the local economy.

Collection Method #1: Local Business Activity Near the Project Site 

• Collect retail data by administering a five-minute intercept survey to several stores in the immediate vicinity of your site.

• Get a sense from store owners about whether they think your project has had a positive impact on business activity.

• Access retail sales data that is not self-reported from local government tax records, but note there is typically a 1 to 2 year delay in that data being collected and reported back to the public.

Collection Method #2:  Property Value Records from Your Local Government

• Access publicly available property tax assessment data from your local government.

• Consider properties within a mile of your project site and measure property value increases over a five- to six-year period to get a full picture data trends.

• If you notice property values rising around your project site, find a control site in your community similar to yours and conduct a similar analysis.

• For a more extensive and complex analysis, perform a hedonic regression — a statistical analysis used in real estate valuation analyzing how various factors in a community influence property values.

If you incorporated a public intercept survey as part of your Green Infrastructure (GI) benefits measurement plan, use some of best practices listed below to assist you in survey creation and administration:

1. Be clear about the feedback you need (finalize your survey questions).

• The starting point for survey administration should always be: what information do you most need from your community? What questions are you trying to answer about your GI project?

• NRPA provides you with the RAND Park Intercept survey and its own GI Community Tool; each contain a good diversity of questions cutting across many possible GI benefits.

• Only use these instruments if the questions are relevant to your project. You also can pick and choose questions from these (or other) surveys to suit your needs and create your own instrument.

• Aim to ask eight-to-ten questions AT MOST. Be selective and choose the most relevant questions related to your project's goals.

Most importantly:

• Make sure survey questions are clearly connected to benefits that your GI project could produce.

• Make sure questions provide you with information you need to replicate bright spots and address weaknesses for future projects (see Step 3 for more details on continuous improvement).

2. Know your community members (clarify your respondents).

• Who are the people who live within a few blocks of your GI project?

• Who are the avid park users, as well as the residents who may not be aware of your work?

• Are there marginalized populations in your community (those with disabilities, seniors, people of color) whose voices must be included? 

• How was the community using the park where your project is located? 

• Where do community members gather to socialize, voice concerns, make plans for the neighborhood, etc.?

3. Decide how to reach them (get a high number of responses).

• Once you have answered the questions above about your community members (a.k.a. your survey respondents), what is the best venue to get your pre- and post-construction responses?

• Various venues for administering your survey that may make sense, depending on your community:
- Neighborhood association meetings
- The park where your GI project is located
- Door-to-door on the streets surrounding your project
- Information sessions specifically covering your project

A few tips about your actual administration when you get to the day-of:

• Have a known entity administer the survey: Pick volunteers who are known in the neighborhood — trusted, informal leaders the community knows and respects — or your staff members who have spoken with the community previously. Utilizing a known entity will boost your response rate, and heighten trust in your project and your surveying efforts.

• Aim for a response pool that reflects your community: Get a diverse pool of respondents (e.g. age, race, gender and ability level) and reach frequent park users, infrequent park users, nearby residents, and park visitors coming from far away. If you identified a target population for the project (e.g., children from a nearby school), make sure to get a high number of responses from those individuals.

4. Have the resources you need (to administer your survey and analyze results).

• Do you have staff available within your organization to assist you in administering your survey and analyzing the results?

• If you have available staff, do any of them have experience in crafting good survey questions?

• The RAND and NRPA surveys provided in this Framework will be a good start; you can administer those surveys as they are. But consider getting internal or external assistance if you need to create your own questions. The priority for survey questions is to ensure they connect to your project’s goals, and that they will get you the feedback you need from the community

• Allocate 40 to 50 hours of staff time to create and administer the survey in the field, both before and after project construction, and to analyze and report on the results.

• When is it necessary to have a third party administer your survey and analyze results? It depends on the level of rigor you desire for your data. Collaborating with a university or research consultant will likely give you higher-quality respondent sampling and data quality, but third parties can be costly and time-intensive.