How a signature image in an email affects clickthrough rate
Experiment ID: #5435
Hillsdale College
Experiment Summary
Timeframe: 09/29/2016 - 10/01/2016
Hillsdale College was announcing their new course about the Supreme Court. For years, they had included a picture of their President’s signature in each email, much like their direct mail letters.
But they hypothesized that this image might decrease the credibility of the email, since people don’t traditionally sign emails.
They decided to quantify the impact of the visual “signature” by creating a treatment that removed the image and left the plain-text signature. They measured clickthrough rate as the effective metric to determine trust.
Research Question
Will removing a signature increase clickthrough rate?
Design
C: Signature
Array
(
[0] => Array
(
[ID] => 13102
[id] => 13102
[title] => Screen-Shot-2016-09-30-at-8.53.46-PM.png
[filename] => Screen-Shot-2016-09-30-at-8.53.46-PM.png
[filesize] => 0
[url] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM.png
[link] => https://www.nextafter.com/experiments/how-a-signature-image-in-an-email-affects-clickthrough-rate/attachment/screen-shot-2016-09-30-at-8-53-46-pm-png/
[alt] =>
[author] => 6
[description] =>
[caption] =>
[name] => screen-shot-2016-09-30-at-8-53-46-pm-png
[status] => inherit
[uploaded_to] => 13101
[date] => 2021-02-25 05:28:46
[modified] => 2021-02-25 05:28:46
[menu_order] => 0
[mime_type] => image/png
[type] => image
[subtype] => png
[icon] => https://www.nextafter.com/wp-includes/images/media/default.png
[width] => 591
[height] => 627
[sizes] => Array
(
[thumbnail] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-150x150.png
[thumbnail-width] => 150
[thumbnail-height] => 150
[medium] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-283x300.png
[medium-width] => 283
[medium-height] => 300
[medium_large] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM.png
[medium_large-width] => 591
[medium_large-height] => 627
[large] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM.png
[large-width] => 591
[large-height] => 627
[1536x1536] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM.png
[1536x1536-width] => 591
[1536x1536-height] => 627
[2048x2048] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM.png
[2048x2048-width] => 591
[2048x2048-height] => 627
[tp-image-grid] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM.png
[tp-image-grid-width] => 591
[tp-image-grid-height] => 627
[post-thumbnail] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-150x150.png
[post-thumbnail-width] => 150
[post-thumbnail-height] => 150
[admin] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-47x50.png
[admin-width] => 47
[admin-height] => 50
[full] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM.png
[full-width] => 591
[full-height] => 627
[thumb_372] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-372x395.png
[thumb_372-width] => 372
[thumb_372-height] => 395
[single_post_thumbnail] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-589x625.png
[single_post_thumbnail-width] => 589
[single_post_thumbnail-height] => 625
[thumb_32_32] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-30x32.png
[thumb_32_32-width] => 30
[thumb_32_32-height] => 32
[thumb_48_48] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-45x48.png
[thumb_48_48-width] => 45
[thumb_48_48-height] => 48
[thumb_64_64] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-60x64.png
[thumb_64_64-width] => 60
[thumb_64_64-height] => 64
[thumb_128_128] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-121x128.png
[thumb_128_128-width] => 121
[thumb_128_128-height] => 128
[thumb_122_67] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-63x67.png
[thumb_122_67-width] => 63
[thumb_122_67-height] => 67
[thumb_153_153] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-144x153.png
[thumb_153_153-width] => 144
[thumb_153_153-height] => 153
[thumb_130_163] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-130x138.png
[thumb_130_163-width] => 130
[thumb_130_163-height] => 138
[thumb_232_177] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-167x177.png
[thumb_232_177-width] => 167
[thumb_232_177-height] => 177
[thumb_272_325] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-544x577.png
[thumb_272_325-width] => 544
[thumb_272_325-height] => 577
[thumb_271_346] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-271x288.png
[thumb_271_346-width] => 271
[thumb_271_346-height] => 288
[thumb_271_271] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-255x271.png
[thumb_271_271-width] => 255
[thumb_271_271-height] => 271
[thumb_272_172] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-162x172.png
[thumb_272_172-width] => 162
[thumb_272_172-height] => 172
[thumb_372_461] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-372x395.png
[thumb_372_461-width] => 372
[thumb_372_461-height] => 395
[thumb_372_500] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-372x395.png
[thumb_372_500-width] => 372
[thumb_372_500-height] => 395
[thumb_385_270] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-254x270.png
[thumb_385_270-width] => 254
[thumb_385_270-height] => 270
[thumb_416_241] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-227x241.png
[thumb_416_241-width] => 227
[thumb_416_241-height] => 241
[thumb_448_410] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-386x410.png
[thumb_448_410-width] => 386
[thumb_448_410-height] => 410
[thumb_448_410_retina] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM.png
[thumb_448_410_retina-width] => 591
[thumb_448_410_retina-height] => 627
[thumb_574_382] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-360x382.png
[thumb_574_382-width] => 360
[thumb_574_382-height] => 382
[thumb_776_395] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-372x395.png
[thumb_776_395-width] => 372
[thumb_776_395-height] => 395
[gform-image-choice-sm] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM.png
[gform-image-choice-sm-width] => 283
[gform-image-choice-sm-height] => 300
[gform-image-choice-md] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM.png
[gform-image-choice-md-width] => 377
[gform-image-choice-md-height] => 400
[gform-image-choice-lg] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM.png
[gform-image-choice-lg-width] => 566
[gform-image-choice-lg-height] => 600
)
)
[1] => Array
(
[ID] => 13103
[id] => 13103
[title] => Screen-Shot-2016-09-30-at-8.54.02-PM.png
[filename] => Screen-Shot-2016-09-30-at-8.54.02-PM.png
[filesize] => 0
[url] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM.png
[link] => https://www.nextafter.com/experiments/how-a-signature-image-in-an-email-affects-clickthrough-rate/attachment/screen-shot-2016-09-30-at-8-54-02-pm-png/
[alt] =>
[author] => 6
[description] =>
[caption] =>
[name] => screen-shot-2016-09-30-at-8-54-02-pm-png
[status] => inherit
[uploaded_to] => 13101
[date] => 2021-02-25 05:28:52
[modified] => 2021-02-25 05:28:52
[menu_order] => 0
[mime_type] => image/png
[type] => image
[subtype] => png
[icon] => https://www.nextafter.com/wp-includes/images/media/default.png
[width] => 592
[height] => 453
[sizes] => Array
(
[thumbnail] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-150x150.png
[thumbnail-width] => 150
[thumbnail-height] => 150
[medium] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-300x230.png
[medium-width] => 300
[medium-height] => 230
[medium_large] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM.png
[medium_large-width] => 592
[medium_large-height] => 453
[large] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM.png
[large-width] => 592
[large-height] => 453
[1536x1536] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM.png
[1536x1536-width] => 592
[1536x1536-height] => 453
[2048x2048] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM.png
[2048x2048-width] => 592
[2048x2048-height] => 453
[tp-image-grid] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM.png
[tp-image-grid-width] => 592
[tp-image-grid-height] => 453
[post-thumbnail] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-150x150.png
[post-thumbnail-width] => 150
[post-thumbnail-height] => 150
[admin] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-50x38.png
[admin-width] => 50
[admin-height] => 38
[full] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM.png
[full-width] => 592
[full-height] => 453
[thumb_372] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-372x285.png
[thumb_372-width] => 372
[thumb_372-height] => 285
[single_post_thumbnail] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM.png
[single_post_thumbnail-width] => 592
[single_post_thumbnail-height] => 453
[thumb_32_32] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-32x24.png
[thumb_32_32-width] => 32
[thumb_32_32-height] => 24
[thumb_48_48] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-48x37.png
[thumb_48_48-width] => 48
[thumb_48_48-height] => 37
[thumb_64_64] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-64x49.png
[thumb_64_64-width] => 64
[thumb_64_64-height] => 49
[thumb_128_128] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-128x98.png
[thumb_128_128-width] => 128
[thumb_128_128-height] => 98
[thumb_122_67] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-88x67.png
[thumb_122_67-width] => 88
[thumb_122_67-height] => 67
[thumb_153_153] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-153x117.png
[thumb_153_153-width] => 153
[thumb_153_153-height] => 117
[thumb_130_163] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-130x99.png
[thumb_130_163-width] => 130
[thumb_130_163-height] => 99
[thumb_232_177] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-232x177.png
[thumb_232_177-width] => 232
[thumb_232_177-height] => 177
[thumb_272_325] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-544x416.png
[thumb_272_325-width] => 544
[thumb_272_325-height] => 416
[thumb_271_346] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-271x207.png
[thumb_271_346-width] => 271
[thumb_271_346-height] => 207
[thumb_271_271] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-271x207.png
[thumb_271_271-width] => 271
[thumb_271_271-height] => 207
[thumb_272_172] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-225x172.png
[thumb_272_172-width] => 225
[thumb_272_172-height] => 172
[thumb_372_461] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-372x285.png
[thumb_372_461-width] => 372
[thumb_372_461-height] => 285
[thumb_372_500] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-372x285.png
[thumb_372_500-width] => 372
[thumb_372_500-height] => 285
[thumb_385_270] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-353x270.png
[thumb_385_270-width] => 353
[thumb_385_270-height] => 270
[thumb_416_241] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-315x241.png
[thumb_416_241-width] => 315
[thumb_416_241-height] => 241
[thumb_448_410] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-448x343.png
[thumb_448_410-width] => 448
[thumb_448_410-height] => 343
[thumb_448_410_retina] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM.png
[thumb_448_410_retina-width] => 592
[thumb_448_410_retina-height] => 453
[thumb_574_382] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-499x382.png
[thumb_574_382-width] => 499
[thumb_574_382-height] => 382
[thumb_776_395] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-516x395.png
[thumb_776_395-width] => 516
[thumb_776_395-height] => 395
[gform-image-choice-sm] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM.png
[gform-image-choice-sm-width] => 300
[gform-image-choice-sm-height] => 230
[gform-image-choice-md] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM.png
[gform-image-choice-md-width] => 400
[gform-image-choice-md-height] => 306
[gform-image-choice-lg] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM.png
[gform-image-choice-lg-width] => 592
[gform-image-choice-lg-height] => 453
)
)
)
T1: No Signature
Array
(
[0] => Array
(
[ID] => 13102
[id] => 13102
[title] => Screen-Shot-2016-09-30-at-8.53.46-PM.png
[filename] => Screen-Shot-2016-09-30-at-8.53.46-PM.png
[filesize] => 0
[url] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM.png
[link] => https://www.nextafter.com/experiments/how-a-signature-image-in-an-email-affects-clickthrough-rate/attachment/screen-shot-2016-09-30-at-8-53-46-pm-png/
[alt] =>
[author] => 6
[description] =>
[caption] =>
[name] => screen-shot-2016-09-30-at-8-53-46-pm-png
[status] => inherit
[uploaded_to] => 13101
[date] => 2021-02-25 05:28:46
[modified] => 2021-02-25 05:28:46
[menu_order] => 0
[mime_type] => image/png
[type] => image
[subtype] => png
[icon] => https://www.nextafter.com/wp-includes/images/media/default.png
[width] => 591
[height] => 627
[sizes] => Array
(
[thumbnail] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-150x150.png
[thumbnail-width] => 150
[thumbnail-height] => 150
[medium] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-283x300.png
[medium-width] => 283
[medium-height] => 300
[medium_large] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM.png
[medium_large-width] => 591
[medium_large-height] => 627
[large] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM.png
[large-width] => 591
[large-height] => 627
[1536x1536] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM.png
[1536x1536-width] => 591
[1536x1536-height] => 627
[2048x2048] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM.png
[2048x2048-width] => 591
[2048x2048-height] => 627
[tp-image-grid] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM.png
[tp-image-grid-width] => 591
[tp-image-grid-height] => 627
[post-thumbnail] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-150x150.png
[post-thumbnail-width] => 150
[post-thumbnail-height] => 150
[admin] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-47x50.png
[admin-width] => 47
[admin-height] => 50
[full] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM.png
[full-width] => 591
[full-height] => 627
[thumb_372] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-372x395.png
[thumb_372-width] => 372
[thumb_372-height] => 395
[single_post_thumbnail] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-589x625.png
[single_post_thumbnail-width] => 589
[single_post_thumbnail-height] => 625
[thumb_32_32] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-30x32.png
[thumb_32_32-width] => 30
[thumb_32_32-height] => 32
[thumb_48_48] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-45x48.png
[thumb_48_48-width] => 45
[thumb_48_48-height] => 48
[thumb_64_64] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-60x64.png
[thumb_64_64-width] => 60
[thumb_64_64-height] => 64
[thumb_128_128] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-121x128.png
[thumb_128_128-width] => 121
[thumb_128_128-height] => 128
[thumb_122_67] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-63x67.png
[thumb_122_67-width] => 63
[thumb_122_67-height] => 67
[thumb_153_153] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-144x153.png
[thumb_153_153-width] => 144
[thumb_153_153-height] => 153
[thumb_130_163] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-130x138.png
[thumb_130_163-width] => 130
[thumb_130_163-height] => 138
[thumb_232_177] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-167x177.png
[thumb_232_177-width] => 167
[thumb_232_177-height] => 177
[thumb_272_325] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-544x577.png
[thumb_272_325-width] => 544
[thumb_272_325-height] => 577
[thumb_271_346] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-271x288.png
[thumb_271_346-width] => 271
[thumb_271_346-height] => 288
[thumb_271_271] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-255x271.png
[thumb_271_271-width] => 255
[thumb_271_271-height] => 271
[thumb_272_172] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-162x172.png
[thumb_272_172-width] => 162
[thumb_272_172-height] => 172
[thumb_372_461] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-372x395.png
[thumb_372_461-width] => 372
[thumb_372_461-height] => 395
[thumb_372_500] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-372x395.png
[thumb_372_500-width] => 372
[thumb_372_500-height] => 395
[thumb_385_270] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-254x270.png
[thumb_385_270-width] => 254
[thumb_385_270-height] => 270
[thumb_416_241] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-227x241.png
[thumb_416_241-width] => 227
[thumb_416_241-height] => 241
[thumb_448_410] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-386x410.png
[thumb_448_410-width] => 386
[thumb_448_410-height] => 410
[thumb_448_410_retina] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM.png
[thumb_448_410_retina-width] => 591
[thumb_448_410_retina-height] => 627
[thumb_574_382] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-360x382.png
[thumb_574_382-width] => 360
[thumb_574_382-height] => 382
[thumb_776_395] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM-372x395.png
[thumb_776_395-width] => 372
[thumb_776_395-height] => 395
[gform-image-choice-sm] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM.png
[gform-image-choice-sm-width] => 283
[gform-image-choice-sm-height] => 300
[gform-image-choice-md] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM.png
[gform-image-choice-md-width] => 377
[gform-image-choice-md-height] => 400
[gform-image-choice-lg] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.53.46-PM.png
[gform-image-choice-lg-width] => 566
[gform-image-choice-lg-height] => 600
)
)
[1] => Array
(
[ID] => 13103
[id] => 13103
[title] => Screen-Shot-2016-09-30-at-8.54.02-PM.png
[filename] => Screen-Shot-2016-09-30-at-8.54.02-PM.png
[filesize] => 0
[url] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM.png
[link] => https://www.nextafter.com/experiments/how-a-signature-image-in-an-email-affects-clickthrough-rate/attachment/screen-shot-2016-09-30-at-8-54-02-pm-png/
[alt] =>
[author] => 6
[description] =>
[caption] =>
[name] => screen-shot-2016-09-30-at-8-54-02-pm-png
[status] => inherit
[uploaded_to] => 13101
[date] => 2021-02-25 05:28:52
[modified] => 2021-02-25 05:28:52
[menu_order] => 0
[mime_type] => image/png
[type] => image
[subtype] => png
[icon] => https://www.nextafter.com/wp-includes/images/media/default.png
[width] => 592
[height] => 453
[sizes] => Array
(
[thumbnail] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-150x150.png
[thumbnail-width] => 150
[thumbnail-height] => 150
[medium] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-300x230.png
[medium-width] => 300
[medium-height] => 230
[medium_large] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM.png
[medium_large-width] => 592
[medium_large-height] => 453
[large] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM.png
[large-width] => 592
[large-height] => 453
[1536x1536] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM.png
[1536x1536-width] => 592
[1536x1536-height] => 453
[2048x2048] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM.png
[2048x2048-width] => 592
[2048x2048-height] => 453
[tp-image-grid] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM.png
[tp-image-grid-width] => 592
[tp-image-grid-height] => 453
[post-thumbnail] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-150x150.png
[post-thumbnail-width] => 150
[post-thumbnail-height] => 150
[admin] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-50x38.png
[admin-width] => 50
[admin-height] => 38
[full] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM.png
[full-width] => 592
[full-height] => 453
[thumb_372] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-372x285.png
[thumb_372-width] => 372
[thumb_372-height] => 285
[single_post_thumbnail] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM.png
[single_post_thumbnail-width] => 592
[single_post_thumbnail-height] => 453
[thumb_32_32] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-32x24.png
[thumb_32_32-width] => 32
[thumb_32_32-height] => 24
[thumb_48_48] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-48x37.png
[thumb_48_48-width] => 48
[thumb_48_48-height] => 37
[thumb_64_64] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-64x49.png
[thumb_64_64-width] => 64
[thumb_64_64-height] => 49
[thumb_128_128] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-128x98.png
[thumb_128_128-width] => 128
[thumb_128_128-height] => 98
[thumb_122_67] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-88x67.png
[thumb_122_67-width] => 88
[thumb_122_67-height] => 67
[thumb_153_153] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-153x117.png
[thumb_153_153-width] => 153
[thumb_153_153-height] => 117
[thumb_130_163] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-130x99.png
[thumb_130_163-width] => 130
[thumb_130_163-height] => 99
[thumb_232_177] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-232x177.png
[thumb_232_177-width] => 232
[thumb_232_177-height] => 177
[thumb_272_325] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-544x416.png
[thumb_272_325-width] => 544
[thumb_272_325-height] => 416
[thumb_271_346] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-271x207.png
[thumb_271_346-width] => 271
[thumb_271_346-height] => 207
[thumb_271_271] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-271x207.png
[thumb_271_271-width] => 271
[thumb_271_271-height] => 207
[thumb_272_172] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-225x172.png
[thumb_272_172-width] => 225
[thumb_272_172-height] => 172
[thumb_372_461] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-372x285.png
[thumb_372_461-width] => 372
[thumb_372_461-height] => 285
[thumb_372_500] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-372x285.png
[thumb_372_500-width] => 372
[thumb_372_500-height] => 285
[thumb_385_270] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-353x270.png
[thumb_385_270-width] => 353
[thumb_385_270-height] => 270
[thumb_416_241] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-315x241.png
[thumb_416_241-width] => 315
[thumb_416_241-height] => 241
[thumb_448_410] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-448x343.png
[thumb_448_410-width] => 448
[thumb_448_410-height] => 343
[thumb_448_410_retina] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM.png
[thumb_448_410_retina-width] => 592
[thumb_448_410_retina-height] => 453
[thumb_574_382] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-499x382.png
[thumb_574_382-width] => 499
[thumb_574_382-height] => 382
[thumb_776_395] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM-516x395.png
[thumb_776_395-width] => 516
[thumb_776_395-height] => 395
[gform-image-choice-sm] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM.png
[gform-image-choice-sm-width] => 300
[gform-image-choice-sm-height] => 230
[gform-image-choice-md] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM.png
[gform-image-choice-md-width] => 400
[gform-image-choice-md-height] => 306
[gform-image-choice-lg] => https://www.nextafter.com/wp-content/uploads/Screen-Shot-2016-09-30-at-8.54.02-PM.png
[gform-image-choice-lg-width] => 592
[gform-image-choice-lg-height] => 453
)
)
)
Results
| Treatment Name | Click Rate | Relative Difference | Confidence | |
|---|---|---|---|---|
| C: | Signature | 1.2% | ||
| T1: | No Signature | 1.3% | 12.9% | 100.0% |
This experiment has a required sample size of 42,228 in order to be valid. Since the experiment had a total sample size of 541,536, and the level of confidence is above 95% the experiment results are valid.
Flux Metrics Affected
The Flux Metrics analyze the three primary metrics that affect revenue (traffic, conversion rate, and average gift). This experiment produced the following results:
12.9% increase in traffic
Ă— 0% increase in conversion rate
Ă— 0% increase in average gift
Key Learnings
The treatment, without the signature, produced a 12.9% lift in clickthrough rate. This indicates that the signature had a slight effect on reducing the recipient’s trust of the sender, which resulted in fewer recipients taking action.
The signature image is a good example of a skeumorphic device, which is an ornamental design feature retained from previous design—in this case, a direct mail letter.
While skeumorphic devices can be helpful initially to maintain visual continuity for users, they can also reduce the “native” appearance and increase perception that the communication is not really from a person.