6 Ways to Measure Your Silent Auction's Fundraising Success

When your nonprofit hosts a silent auction fundraising event, most of the planning process is typically focused on logistical details and procuring auction items. After all, your supporters are more likely to attend a well-organized event that features prizes they’re excited to bid on!

However, there are two other critical steps in planning a successful silent auction that are sometimes overlooked. The first is taking the time to set specific, achievable goals for your fundraiser, and the second is determining how you’ll know if you reached those goals after the event ends.

There are a variety of objectives you could be working toward as you plan your fundraiser, and each of them will be best measured by a different metric. In this guide, we’ll look at six popular metrics nonprofits use to evaluate their silent auction’s fundraising success, including:

Return on Investment (ROI)
Items Sold
Donor Acquisition Rate
Donor Retention Rate
Marketing Conversions
Participant Satisfaction

Applying any or all of these metrics to your nonprofit’s silent auctions will help you identify what you did well, where there is room for improvement, and how you can adjust your strategy as you plan future auctions. Let’s dive in!

1. Return on Investment (ROI)

One of the easiest metrics to calculate from your silent auction fundraising data is the total amount raised from ticket sales, winning bids, financial sponsorships, and additional donations made during the event. However, this doesn’t take into account the upfront expenses that tend to be associated with auctions—venue rentals, fundraising software payments, marketing materials, any prizes that your organization purchased rather than receiving as in-kind donations, and more.

Return on investment (ROI) is a more holistic metric that considers both the revenue your nonprofit generates from your silent auction and the expenses you incurred while planning it. You can calculate it using the following equation:

ROI = [(Total Amount Raised – Total Costs) / Total Costs] x 100

If your ROI is negative, it means that your auction cost more money than it raised, and you’ll need to find ways to reduce your expenses when planning future events. On the other hand, a positive ROI means your auction was financially successful. Ideally, you’d want your ROI to be a larger positive number, as this would indicate that you raised significantly more money than you spent.

2. Items Sold

At an auction, the items are the star of the show. Plus, procurement is often the most time-consuming and resource-intensive part of the planning process. So, it makes sense to include metrics related to the sale of your silent auction items when evaluating your fundraising success.

Review the completed bid sheets from your event to calculate the following item-related metrics:

Sell-through rate. This is simply the percentage of items that sold at your silent auction. For instance, if you had 100 prizes up for auction and 95 of them were purchased by participants, your sell-through rate would be 95%.
Average bid amount. Determine this number by adding up all of your supporters’ winning bids, then divide by the number of items sold. This metric demonstrates how valuable participants perceived your items to be.
Number of items that sold at or above their fair market value (FMV). Winspire defines FMV as “[an auction] item’s worth relative to what supporters would pay if they purchased it elsewhere.” Since participants often choose to purchase items at auction because they’re hoping for a discount they couldn’t get otherwise, any prizes that sell at or above their FMV are particularly appealing to your supporter base.

Knowing this information about the items that sold at your silent auction can help you hone the procurement process for future auctions—you can make sure to find items that your supporters are interested in and perceive as high-value to maximize your ROI.

3. Donor Acquisition Rate

In the context of a silent auction, donor acquisition rate refers to the percentage of participants who engaged with your nonprofit for the first time by attending your event. If 200 people participated in your silent auction and 80 of them were first-time supporters of your organization, your donor acquisition rate would be 40%.

Auctions are particularly effective for attracting new supporters because while some participants will sign up specifically to contribute to your nonprofit, others just want to purchase one-of-a-kind items that also happen to support a good cause. Make sure to follow up with these new donors after your auction to encourage them to learn more about your mission and stay involved with your organization.

4. Donor Retention Rate

Donor acquisition and retention are complementary to one another. Acquisition allows your organization to engage more community members and plan for growth, and retention helps you cultivate lasting relationships with supporters and sustainably fund your mission.

The most common way to calculate donor retention rates in the context of silent auctions is to determine the percentage of participants from a previous auction that also attended your most recent one. For example, if 75 of the 150 supporters who participated in last year’s silent auction came to this year’s event as well, your donor retention rate would be 50%.

5. Marketing Conversions

Leveraging multiple print and digital marketing channels is essential for attracting as many participants to your silent auction as possible. After the event, conversion data can help you determine which methods were most effective for generating registrations.

Track the number of auction signups from each of the following promotion channels:

Direct mail invitations
Email marketing messages
Your nonprofit’s various social media accounts
Google Search Ads
Redirections to your event registration form from other pages on your website

Understanding which methods compel the most supporters to register can help you allocate your marketing budget more effectively in the future. For instance, if you find that direct mail had the lowest conversion rate of any channel and social media generated the most signups, you may decide to reduce your spending on mailed invitations and instead put that money toward paid ads on Instagram and Facebook for your next auction.

6. Participant Satisfaction

Participant satisfaction is a less objective measurement than the other fundraising success metrics discussed above. However, it’s still important to consider when evaluating your silent auction. After all, a major purpose of nonprofit events is to bring your community together around a cause, and learning what supporters thought about your auction can tell you whether you did this effectively.

Post-event surveys are one of the best ways to track participant satisfaction. MemberClicks’ guide to event feedback surveys recommends referencing your auction check-in list to ensure you get feedback from actual participants and incentivizing survey completion by entering respondents’ names into a drawing for a gift card or branded merchandise. Additionally, include both multiple-choice and open-ended questions on your survey to encourage supporters to share their honest opinions.

The metrics your nonprofit will find most useful will depend on the primary goal of your silent auction. If the main objective is revenue generation, your ROI and item-related data analysis will tell you how successful your event was. Marketing conversions are the most important metrics if your goal is to spread awareness about your organization. And measuring donor acquisition, retention, and satisfaction is essential if you’re focused on supporter engagement.

No matter how you plan to measure your silent auction’s success, make sure to store all of your event data in one place so it’s easier to analyze and evaluate. Happy fundraising!