Gabor Granger
This article helps you add a Gabor Granger (Gabor-Granger) question in SurveyMars, set the prices and stop rules, and read the breakpoint price, optimal price, estimated virtual revenue, and T2B.
Overview
Gabor Granger measures purchase intention at several prices before you set a final price. You enter the prices in advance. SurveyMars asks respondents how likely they are to buy at those prices, then highlights the psychological price ceiling and the price with higher revenue potential.
Purchase intention means the respondent chose one of the two highest-scored options on the scale. Estimated virtual revenue = price × the share of respondents with purchase intention. A higher virtual revenue means that price is more likely to produce higher actual revenue.
Use Cases
- Launch pricing: Test candidate prices before release and find a price that still has strong purchase intention and higher virtual revenue.
- Price changes: Estimate how a higher or lower price may change the purchase rate and overall revenue.
- Price tiers: See which prices the mass market is more likely to accept, and whether a higher tier still fits respondents who remain willing to buy.
Feature Access
1. Open the survey editor.
2. In the question type list, open Research question types.
3. Select Gabor Granger and add it to the survey.
Set Test Prices and Question Text
After you add the question, set the prices included in the test. During the survey, respondents rate purchase intention at these prices. The settings window has two sides: settings on the left, and a preview on the right that matches the response page.
1. Select the Gabor Granger question and click Set Gabor Granger.
2. Add or delete prices on the left. Prices are sorted in ascending order by default. Enter every price in the same currency unit.
3. Click input to customize the purchase-intention question text.
4. Edit the scale labels in the scale options on the left. Purchase intention is always counted from the two highest-scored options, so keep those two labels as willing-to-buy choices.
How the Question Appears in the Editor
The editor preview uses the response-page layout by default. Respondents see one price at a time.
1. Keep Single-question answering selected to preview the question as it appears on the response page.
2. The question settings keep Automatically go to the next question. Set prices, wording, and stop rules with Set Gabor Granger.
Purchase Intention While Answering
Each price asks for purchase intention on a 5-point scale. The two highest-scored options count as purchase intention. In the default wording, those options are usually Probably would buy and Definitely would buy.
For example, if 200 people answer a price and 142 choose those two options, the purchase-intention share at that price is 71%.
Stop at the Breakpoint
During a response, a Gabor Granger is the point where purchase intention reverses as the price moves up or down. You can choose how the question ends when that reversal appears.
1. Select Stop answering at the Gabor Granger.
- SurveyMars shows a random starting price, and the respondent begins there.
- When a breakpoint appears, the question stops. It does not continue to the edge of the price range.
2. To keep checking intention while the price goes down, also select Probe below the breakpoint.
- If the price is decreasing and a breakpoint appears, answering continues until the respondent chooses Definitely would buy, or the price reaches the lowest value.
- If the price is increasing and purchase intention reverses, answering stops immediately.
View the Gabor Granger Report
After responses are collected, open the aggregated pricing results. The figures come from that question’s statistics table. The same summary structure is reused for each question, with the numbers replaced.
1. Open Statistics & Analysis. On the Gabor Granger question, open the Gabor Granger report.
2. On the statistics report page, open the Gabor Granger Analysis tab on the left.
The report highlights four results:
- Breakpoint price: The price where purchase intention drops most sharply across all respondents. This is the psychological ceiling for most of the target market. The drop is shown in percentage points.
- Optimal price: The price with the highest estimated virtual revenue. Use it as the core price anchor.
- Estimated virtual revenue: Price × the share who would definitely or probably buy. A higher value means that price is more likely to produce higher actual revenue.
- Average T2B intent: The average Top-2-Box purchase intent across the tested prices.
Read the Strategic Insights
The report writes a strategic summary from the statistics table. The figures below are an example. A live report replaces them with the results for your question. The currency symbol is illustrative; use the unit you entered for the prices.
- Breakpoint: When the price exceeds $399, purchase intent drops sharply (by 13.0 percentage points). This price is the psychological threshold.
- Optimal pricing: The highest virtual revenue is at $399. Use this price as the core price anchor.
- Revenue maximization: Virtual revenue peaks near $399. Moving away from this price lowers total revenue potential.
- Demand elasticity: Each additional $100 reduces T2B intent by about 9.5 percentage points, so purchase intent is sensitive to price.
- Mass-market acceptance: T2B is above 50% at $199, $299, and $399. Prices where T2B falls below 50% usually lose most potential buyers.
- Premium opportunity: At $399, 73.0% of respondents still show purchase intent. You can consider a higher price tier for this group.
How T2B Is Calculated
T2B means Top-2-Box. It is the percentage of respondents who chose the two most positive options on the scale. In this question, the last two options—the two with the highest scores, such as “Probably would buy” and “Definitely would buy”—count as purchase intent. You can edit these labels in the scale options on the left of the settings window.
For each price, SurveyMars counts respondents who chose the last two options, divides that count by the number of respondents for that price, and multiplies by 100.
T2B% = (number who chose the last two options / total respondents) × 100
Example: 200 people answer, and 142 choose “Probably would buy” or “Definitely would buy.” T2B = (142 / 200) × 100 = 71%.
T2B is a direct indicator of likely purchase. The breakpoint in the report is the price where T2B falls most sharply. It shows the price ceiling for most of the target market.
Share the Report
Sharing works the same way as for other research reports, such as the PSM report. Open the Gabor Granger report and use the share action on the page to send the results to the people who need them.Click to view how to share the report
Notes
1. Set several prices from low to high, all in the same currency unit. Prices are sorted in ascending order by default.
2. After you edit the scale labels, keep the two highest-scored options as willing-to-buy choices. Otherwise T2B and virtual revenue will no longer describe purchase intention.
3. Use “Probe below the breakpoint” together with “Stop answering at the Gabor Granger.” Downward prices continue until “Definitely would buy” or the lowest price. Upward prices stop as soon as intention reverses.
4. A breakpoint during answering is where one person’s intention reverses. The breakpoint price in the report is where T2B drops most sharply for the whole sample.
5. Amounts, percentage points, and price ranges in the strategic insights come from the current question’s statistics table. Button names follow the version shown in your account.
FAQs
Q: How is Gabor Granger different from PSM?
A: PSM uses four price-perception questions and estimates an acceptable range from where the curves cross. Gabor Granger shows specific prices, asks purchase intention at each one, and uses the T2B drop and virtual revenue to find the breakpoint price and the optimal price.Click to learn about the PSM question type
Q: Which options count as purchase intention?
A: The two highest-scored options. By default these are “Probably would buy” and “Definitely would buy.” You can change the labels. T2B still uses the last two, highest-scored options.
Q: Why can the optimal price and the breakpoint price differ?
A: The breakpoint price is where purchase intention drops most sharply. It marks the psychological ceiling. The optimal price is where estimated virtual revenue is highest, so it balances the price level and the share willing to buy. They may be the same price or two different prices.
Q: How is virtual revenue calculated?
A: Estimated virtual revenue at a price = that price × the share who would definitely or probably buy, which is price × T2B%. Revenue potential is usually higher when the share stays high and the price is still acceptable.
