**Principal Investigator(s):** **Siwei Cheng** New York University Email: [siwei.cheng@nyu.edu][1] Home page: [http://as.nyu.edu/content/nyu-as/as/faculty/siwei-cheng.html][2] **Fangqi Wen** New York University Email: [fw531@nyu.edu][3] Home page: [http://as.nyu.edu/content/nyu-as/as/departments/sociology/people/current-phd-students/wen-fangqi.html ][4] **Sample size**: 3077 **Field period**: 11/19/2017-03/16/2018 **Abstract:** The question of how Americans think about the status of mobility is drawing growing attention from scholars and policymakers who seek to understand its consequences for public opinion and policy support. While previous studies on mobility perceptions have mainly focused on mobility chances for specific income groups or the average population, we propose a new survey instrument that helps assess the public perceptions of the equality of mobility prospects between children from rich and poor families. This survey instrument will generate a measure of subjective mobility perception that can be directly compared against the objective rank-rank slope reported by recent empirical work. **Hypotheses:** For the control group, we have three competing hypotheses: (1) Americans correctly perceive the rank-rank income slope; (2) Americans overstate the rank-rank income slope; (3) Americans understate the rank-rank income slope. For the treatment groups, we have two additional hypotheses: (1) Americans perceive a lower rank-rank income slope for hypothetical individuals who have a college degree than for hypothetical individuals in the general population. (2) Americans perceive a lower rank-rank income slope for hypothetical individuals who work hard in life than for hypothetical individuals in the general population. **Experimental Manipulations:** We randomly assign the respondents to three groups that vary in terms of the characteristics of the hypothetical individual whose mobility prospect is to be evaluated: (1) a control group in which there is no specific description (N=1,858); (2) a "college-graduate" treatment group in which we describe the vignette as having a college degree (N=606); and (3) a "hard-working'' treatment group" in which we describe the vignette as working very hard in life (N=613). **Key Dependent Variables:** Perceived rank-rank slope in parent's and child's income. **Summary of Findings:** We fielded the proposed survey instrument on a nationally representative sample of 3,077 adults in the United States. Our data suggest that the widely-adopted presumption of mobility optimism does not apply to the case of relative mobility (in terms of the equality of mobility chances between children from rich and poor families). Americans actually hold pessimistic perceptions about the equality of economic outcomes between children from richer and poorer families. They overstate the economic prospect for children from rich families and understate the economic prospect for those from poor families. This results in an overstatement of the intergenerational persistence in income. [1]: mailto:siwei.cheng@nyu.edu [2]: http://as.nyu.edu/content/nyu-as/as/faculty/siwei-cheng.html [3]: mailto:fw531@nyu.edu [4]: http://as.nyu.edu/content/nyu-as/as/departments/sociology/people/current-phd-students/wen-fangqi.html