Delay between recruitment and participation impacts on preinclusion attrition

Despite being a common aspect of psychological research, the impact of delay between recruitment and active participation on dropout rates has received little research attention. This is probably due to the intuitive sense that longer delays will increase the dropout rate. Preinclusion attrition diminishes sample sizes and may threaten data representativeness. One hundred and two university undergraduates were recruited to participate in a short, one-off study via Short Message Service (SMS). Upon receipt of an SMS indicating consent to participate, the researchers delayed sending the study questions for one day, one week, one month, or two months. Delay was significantly associated with response rate with an 80% response rate in the one-day delay condition, 56% at one week, and 42% at one month. No responses were received in the two-month delay condition. This research confirms that the delay between recruitment and active participation impacts on preinclusion attrition when conducting research via SMS.