Slider Scale or Text Box: How Response Format Shapes Responses

Transcription

1 MARKETING SCIENCE INSTITUTE WORKING CONCEPTS & PAPER STRATEGIES 2018 Slider Scale or Text Box: How Response Format Shapes Responses Manoj Thomas The Johnson School, Cornell University Ellie Kyung Tuck School of Business, Dartmouth College

2 HOW CAN RESPONSE FORMAT INFLUENCE WTP? Managers and academics use text boxes and slider scales interchangeably when collecting willingness-to-pay and payment information Mobile Interface PRICELINE Web Interface for example, Priceline uses a text box on its website and a slider scale on its mobile interface. Slider scales are seen as easier to use on mobile devices.

3 RESEARCH QUESTION Very few researchers have studied the effect of slider scales v. other formats, with a primary focus versus radio button formats (Couper et al. 2006, Funke 2016, Funke et al. 2011, Roster, Lucianetti, and Albaum 2015) Primary findings: Mixed or no effect on responses; increases response times; increases non-response rates Academics increasingly measure WTP using non-text box formats Journal of Consumer Research papers measuring WTP : Text box = 100% : Text box = 64%; Slider = 23%; Scale = 10% Previous research has not examined the effect of slider scales v. text box on consumer payments: How can the use of text boxes versus slider scales systematically influence consumer responses?

4 ROLE OF THE MENTAL NUMBER LINE When people are asked to place a bid or payment amount or state their WTP, there is some spectrum of possible values they might consider with some implicit notion of what constitutes a low, medium, or high value. Absent a visual cue, people will naturally rely on the mental number line to determine what constitutes low, medium, and high values. With the mental number line, the same objective difference is perceived as larger when closer to the starting point, similar to how differences in light and sound are perceived. For example, a 40 watt difference is easier to perceive when going from 0 to 40 watts than when going from 60 to 100 watts. Perceived magnitude 40 Watts: 0 to Watts: 60 to

5 A NON-LINEAR SCALE FOR MAGNITUDE JUDGMENTS Similarly, the same objective difference, like 10, feels larger when going from $10 to $20 than when going from $60 to $70. Mental Number Line Actual magnitude Perceived magnitude (Adaval 2013; Bagchi and Davis 2016; Cheng and Monroe 2013; Dehaene 2001, 2003; Dehaene and Changeux 1993; Dehaene et al. 2008; Grewal and Marmorstein 1994; Lembregts and Pandelaere 2013; Monroe 1973; Parducci 1965, 1996; Thomas and Morwitz Magnitudes and numbers are usually evaluated on an unbounded, non-linear internal scale Thus, the threshold for what constitutes a low, medium, or high value will not consist of a set of equally spaced category limens, but will be assimilated more towards the starting point as differences closer to the starting point are seen as larger. However, we posit that people s mental number line can change depending on response format.

6 NUMBER LINE FOR TEXT BOXES V. SLIDER SCALES Text box responses are primarily based on comparing numeric value to the starting point TEXT BOX Category Limens Assimilated Towards the Starting Point P START P LOW P MEDIUM P HIGH Slider Scales provide a visual representation of the line, making the visual distance from the starting and end points salient SLIDER SCALE Category Limens Influenced by both the Starting & Ending Points P START P LOW P MEDIUM P HIGH P END Relative to text boxes, category limens on slider scales are assimilated to the endpoint, resulting in more extreme WTP responses. We refer to this as the Endpoint Assimilation Effect.

7 EMPIRICAL TESTING OF ENDPOINT ASSIMILATION EFFECT Relative to text boxes, slider scales intensify WTP responses Increases WTP for ascending payment formats Decreases WTP for descending payment formats For hypothetical and real bids When endpoints are explicit and when they are not Rule out: range salience ease of response movement direction response momentum Contextual factors that alter visualization moderate the effect Effect intensifies with proximity to the endpoint Greater assimilation to the endpoint for higher bids Exps 1a, 1b, 2, 3 Exp 4 Effect attenuates for convex slider scales E.g. where differences near the starting point appear larger Effect intensifies as response range increases Stronger effect for ranges with higher endpoints Exp 5 Exp 6

8 EXP 1A: AUCTION BIDS METHOD 127 Dartmouth undergraduates, in person experiment, subject pool DOMAIN Bid on a Japanese insulated mug DESIGN MEASURES Response format: Text box v. slider (between subjects) Willingness-to-pay for the mug Confirmation of range provided ($0 to $100, $0 to $150, $0 to $200) EXPERIMENTAL PARADIGM BIDDING TASK Opportunity to bid for a Japanese insulated travel mug not available locally Confirmed that they understood that if they placed the winning bid, they would have to pay that amount for the mug Physical mug was available in a box during experimental sessions Included retail price ($24), explicit range ($0 to $150), product photo, and product description

9 EXP 1A: STIMULI TEXT BOX SLIDER

10 EXP 1A: AUCTION BID RESULTS AVERAGE BID $ Text box Slider Average Bid 90% of participants confirmed the correct range outlined in the bidding process Response format: p <.01 Does not stem from failing to consider response range. Does endpoint assimilation manifest when everyone has to pay?

11 EXP 1B: CHARITABLE DONATIONS METHOD 204 mturk participants, paid 51 cents + $1 bonus to potentially donate DOMAIN Donation to Intrepid Fallen Heroes Fund DESIGN MEASURES Response format: Text box v. slider (between subjects) Cents (0 to 100) donated from the $1 bonus EXPERIMENTAL PARADIGM DONATION OPPORTUNITY Experiment was run during Veterans Day Weekend offering participants the donate as much of the unexpected $1 as they would like to the Intrepid Fallen Heroes Fund serving injured or wounded U.S. military personnel Organization description provided with explicit range (0 to 100 cents) Similar to previous study, also provided with average donation amount (17 cents) Note: Have replicated study without average donation and with and without slider labels

12 EXP 1B: STIMULI TEXTBOX SLIDER

13 EXP 1B: DONATION RESULTS AVERAGE DONATION Text box Slider 37.8 $ Average Donation Response format: p <.01 Replicates for real transactions where everyone pays

14 OPEN QUESTIONS Does the effect hold for more externally valid formats? Non-zero starting points No explicit ranges Does the effect hold even for multiple bids after people learn to use the format? Are people aware of the effect?

15 EXP 2: ASCENDING PAYMENT FORMAT (EBAY) METHOD 199 mturk participants, online experiment, paid $1 DOMAIN ebay-style bids on refurbished laptops DESIGN MEASURES Response format: Text box v. slider (between subjects) Starting price level: $239, $259, $279 (within subjects) Willingness-to-pay for 3 laptops Ease / difficulty of placing bid (1 = extremely easy, 5 = extremely difficult) Format Preference (slider v. textbox) Naïve beliefs of effect of bidding format (1: Bids not affected by response format, 2: Bids will be higher using slider, 3: Bids will be higher using textbox) EXPERIMENTAL PARADIGM SCREENING U.S. participants only Computer interfaces only Must have purchased a laptop in the past 24 months or plan to buy one in the next 24 months BIDDING TASK Instructions on how to bid, including example of response format Three laptop computers with different non-zero starting bids were shown in randomized order No range provided Included photograph and product information

16 EXP 2: STIMULI TEXT BOX SLIDER

17 EXP 2: ASCENDING PAYMENT FORMAT RESULTS AVERAGE BID 320 Text box Slider $ $239 $259 $279 Response format: p =.02 Starting price level: p <.001 Interaction: p =.74 Manifests in repeated-measures format Manifests for non-zero starting points

18 EXP 2: ASCENDING PAYMENT FORMAT RESULTS Ease EASE Text box Slider Response Format % Slider Preference AWARENESS FORMAT PREFERENCE Text box Slider 50% 38% 8% F < 1 p <.01 0% Response Format Textbox --> higher bid Slider --> higher bid Bid not affected 5% 21% 74% 0% 50% 100% Does not stem from response ease or format preference The effect seems to be non-conscious

19 OPEN QUESTIONS What happens with a descending payment format? Red lines indicate recalibration of limens that occurs on a slider scale relative to text box P START P L P M P H Ascending payment format: Payments entered are higher than a starting point Descending payment format: Payments entered are lower than a starting point P L P M P H P START Is the endpoint assimilation effect caused by the starting point of the slider knob?

20 EXP 3: DESCENDING PAYMENT FORMAT (PRICELINE) METHOD 333 mturk participants, online experiment, paid $1 DOMAIN Priceline-style Name Your Own Price bids on hotel rooms DESIGN MEASURES Response format: Text box, slide-from-left, slide-from-right (between subjects) City: New York v. Atlanta (within subjects) Median price (starting price level): Low, medium, high (within subjects) Willingness-to-pay for 6 hotel rooms Ease / difficulty of placing bid Format Preference (slider v. textbox) Naïve beliefs of effect of bidding format EXPERIMENTAL PARADIGM SCREENING U.S. participants only Computer interfaces only Must have made a hotel reservation online and stayed in a hotel in the past 24 months BIDDING TASK Instructions on how to bid, including example of response format Six hotel rooms with different starting bids from two cities were shown in randomized order Included location, price, and star-rating

21 EXP 3: STIMULI SLIDER LEFT-TO-RIGHT SLIDER RIGHT-TO-LEFT TEXT BOX If effect is due to endpoint assimilation and not left-to-right movement, both slider conditions should be below the text box condition.

22 EXP 3: DESCENDING PAYMENT FORMAT RESULTS AVERAGE BID Slider-Left-to-Right Slider-Right-to-Left Text box 155 $ Level 1 Level 2 Level 3 Starting price level (median room rates) Response format: p =.01 City: p <.001 Median price: p <.001 Response format x median price: p =.02 City x median price: p <.001 Response format x city: p =.11 3-way interaction: p >.80 In descending payment formats, slider scale responses are lower than text box responses, assimilating towards a left-side endpoint

23 EXP 3: DESCENDING PAYMENT FORMAT RESULTS EASE FORMAT PREFERENCE Ease Slider-Left-to-Right Slider-Right-to-Left Textbox F < 1 Response Format % Slider Preference Slider-Left-to-Right Slider-Right-to-Left Textbox 100% 65% 68% 29% p <.01 0% Reponse Format AWARENESS Textbox --> higher bid Slider --> higher bid 5% 13% Bid not affected 82% 0% 50% 100% Does not stem from left-to-right movement direction or only from anchor placement

24 OPEN QUESTIONS Is the effect caused by physical momentum of the sliding knob? If effects depends on visualization of end point, does it depend on proximity to endpoint? (Response magnitude)

25 EXP 4: MODERATION BY BID SIZE METHOD 333 mturk participants, online experiment, paid $0.51 DOMAIN ebay-style bids on a refurbished laptop DESIGN MEASURES Response format: Text box v. slider v. pick from scale (between subjects) Response magnitude: low, medium, high bid (within subjects) Estimate of low, medium, and high bid sizes of a single product EXPERIMENTAL PARADIGM SCREENING U.S. participants only Computer interfaces only Must have purchased a laptop in the past 24 months or plan to buy one in the next 24 months BIDDING TASK Instructions on how to bid, including example of response format Single laptop shown for 3 bid estimates: low, medium, and high Included photograph and product information, and range (starting bid $259 to price for new computer $949)

26 EXP 4: STIMULI TEXT BOX

27 EXP 4: STIMULI SLIDER PICK If effect is due response momentum, the slider condition should be higher than the pick condition. If the effect is due to endpoint assimilation, the pick condition, which also provides a visualization of the line, should be similar to the slider condition.

28 EXP 4: MODERATION BY BID SIZE (WITHIN SUBJECTS) AVERAGE BID Text box Slider Pick p =.005 p =.93 p <.001 p = $ All p > Low Medium High Bid Levels Response format: p =.004 Response magnitude: p <.01 Interaction: p <.001 Pick and slider conditions are identical: Applies to any format that forces line visualization Effect is moderated by visual proximity to endpoint; stronger for high bids

29 OPEN QUESTIONS If the effect depends on visualization along the number line, what happens if we change the meaning of the physical points along the slider scale? In the following study, we introduce a convex slider scale where the number line is closer to the mental number line, where values closer to the starting point have larger spacing than those closer to the endpoint of the number line.

30 EXP 5: MODERATION BY SLIDER TYPE (CONVEX) METHOD 262 mturk participants, online experiment, paid 51 cents DOMAIN ebay-style bids on refurbished laptops DESIGN MEASURES Response format: Text box, convex slider, linear slider (between subjects) Response magnitude: low, medium, high bid (within subjects) Willingness-to-pay for 3 laptops EXPERIMENTAL PARADIGM SCREENING U.S. participants only Computer interfaces only Must have made a hotel reservation online and stayed in a hotel in the past 24 months BIDDING TASK Instructions on how to bid, including example of response format Six hotel rooms with different starting bids from two cities were shown in randomized order Included location, price, and star-rating

31 EXP 5: CONVEX V. LINEAR SLIDER Bid Values ($) Linear Convex LINEAR SLIDER Markers on the Slider Scale Note that the same physical midpoint on the convex slider scale represents a smaller value than on the linear slider. If the convex slider scale is closer to the mental number line, the values should be similar to those in the text box condition CONVEX SLIDER

32 EXP 5: MODERATION BY SLIDER TYPE (CONVEX) AVERAGE BID 500 p =.01 p =.05 $ p < Textbox Convex Slider Slider Response format: p =.02 Response magnitude: p <.01 Interaction: p <.01 A slider scale (convex) that mirrors the mental number line attenuates the effect

33 OPEN QUESTIONS If the effect depends on assimilation to the endpoint, what happens if we change the meaning of the endpoint? (Increase the response range) If the effect stems from visualization of the response range, varying the endpoint of the response range should only affect responses on slider scales, but not on text boxes.

34 EXP 6: MODERATION BY RANGE METHOD DOMAIN Wine auction DESIGN MEASURES EXPERIMENTAL PARADIGM BIDDING TASK 413 mturk participants, online experiment, paid 51 cents Response format: Text box v. slider (between subjects) Response range: $500 v. $1000 endpoint (between subjects) Response magnitude: Low, medium, and high bid (within subjects) Estimate of low, medium, and high bid for single wine Ask to identify minimum and maximum bid To what extent was your highest bid influenced by the maximum possible bid value? (none at all, a little, a moderate amount, a lot, a great deal) Instructions on how to bid, response range, definition of quality ratings, vintage year, then example of response format Single wine presented $500 v. $1000

35 EXP 6: STIMULI TEXT BOX SLIDER

36 EXP 6: MODERATION BY RANGE RESULTS AVERAGE BID Textbox Slider 137 $ To $500 To $ way interaction: p <.001 Response format: p <.001 Response magnitude: p <.01 Range: p =.20 Response format x Response magnitude: p <.001 Response format x range: p =.37 Response magnitude x range: p <.001 The effect of range has an increasing effect for larger bid sizes only for slider formats and not for text box formats (where range is not visualized)

37 EXP 6: ENDPOINT INFLUENCE ENDPOINT INFLUENCE To what extent was your highest bid influenced by the maximum possible bid value? [Not at all / A little / A moderate amount / A lot / A great deal ] Textbox Slider 1.96 Endpoint influence To $500 To $ way interaction: p <.01 Response format: p =.99 Range: p =.50 While participants in the text box conditions were aware that the larger possible bid values influenced them Larger less, endpoints those the have slider an opposite scale conditions effect in did the not textbox different conditions in their perceived influence of the endpoint and has value, no further effect in underscoring the slider conditions this is an unconscious effect.

38 SUMMARY RESULTS Across our studies For ascending payment formats where slider scales started at a zero value, values solicited through slider scales were on average 66% higher than those solicited through textbox values For ascending payment formats where slider scales started at nonzero values (i.e. $239, $259, $279), values solicited through slider scales were on average 5% higher than those solicited through textboxes (taking into account the starting value, the relative difference between these values in terms of distance from starting point is 52%) For descending payment formats, values solicited through textboxes were on average 10% higher than those solicited through slider scales. SINGLE PAPER META-ANALYSIS 12 STUDIES (7 REPORTED STUDIES + 5 ADDITIONAL STUDIES) Cohen s d =.41 [.33,.48]

39 SUMMARY & CONTRIBUTIONS 1 The use of slider scales v. textboxes intensifies WTP responses 2 The Endpoint Assimilation Effect stems from implicit recalibration of category boundaries that depends on: Payment form: ascending v. descending Distance relative to starting and end point Visualization of number line Magnitude of the endpoint Appendix studies Length of the number line (mobile v. computer interfaces) Attention to endpoint (cash v. credit payments) 3 Applies to any response formats that provide line visualization 4 Not due range salience, ease of response, directionality, response momentum

40 MANAGERIAL IMPLICATIONS 1 For ascending payment formats, slider scales yield higher payment values than text boxes 2 For descending payment formats, text boxes yield higher payment values than text boxes 3 Elements of slider design, such as payment ranges, type of interface (mobile versus web), and tactile interactions can all have an affect on consumer payments 4 All linear response formats can have a similar effect

41 Questions? Manoj Thomas: Ellie Kyung: