Closeness of the Friend (CLOS)

Abstract

The Closeness of the Friend (CLOS) scale is a concise, psychometrically robust three-item self-report instrument engineered to assess subjective relational closeness, interpersonal connection, and affective regard toward a designated friend or companion. Introduced by Liu and Min (2020) in their seminal investigation of interpersonal preference expression within joint consumption dyads, the scale addresses the persistent methodological need for a rapid, low-burden assessment of perceived dyadic closeness. The instrument prompts participants to evaluate an identified individual along three primary evaluative dimensions: subjective felt closeness, felt connectedness, and generalized liking. Responses are collected utilizing a 7-point Likert response format anchored from 1 ("Not at all") to 7 ("Very much"), which are averaged to yield an overall composite index of relational closeness.

Psychometrically, the CLOS exhibits exceptional internal consistency, with Cronbach's alpha coefficients routinely exceeding .90 across empirical investigations of consumer choices, social dynamics, and dyadic negotiations. Confirmatory factor analyses corroborate a strictly unidimensional latent factor structure with standardized factor loadings consistently surpassing .85. The instrument demonstrates strong convergent validity with established relational constructs—including the Inclusion of Other in the Self (IOS) Scale and the Relationship Closeness Inventory (RCI)—while offering superior administrative brevity and lower cognitive load. Consequently, the CLOS represents a vital measurement tool across experimental social psychology, consumer behavior, behavioral economics, and clinical relationship science where participant burden must be minimized without sacrificing measurement fidelity.

Keywords

Relational closeness, dyadic decision-making, interpersonal connection, joint consumption, social psychology, friendship measurement, psychological intimacy, perceived connection, interpersonal liking, preference expression asymmetry, dyadic research, psychometrics

Authors

The Closeness of the Friend (CLOS) scale was operationalized and validated by:

• Peggy J. Liu, Ph.D. — Ben L. Fryrear Chair in Marketing and Professor of Business Administration, Joseph M. Katz Graduate School of Business, University of Pittsburgh. Dr. Liu's research centers on consumer behavior, interpersonal dynamics in consumption, and health-related decision-making.
• Kate E. Min, Ph.D. — Visiting Assistant Professor of Marketing, SC Johnson College of Business, Cornell University. Dr. Min investigates social interactions, goal pursuit, and consumer welfare within dyadic and group contexts.

Correspondence regarding the original experimental application can be directed to the primary authors via the Journal of Marketing Research publication infrastructure or institutional communication channels.

Purpose

The primary purpose of the CLOS scale is to quantify an individual's subjective sense of intimacy, solidarity, and positive valence toward a specific dyadic partner within experimental and field investigations. Contemporary behavioral research frequently probes interpersonal processes—such as joint decision-making, collaborative problem-solving, altruistic sacrifice, and shared consumption experiences. In these investigative paradigms, researchers require a validated metric to either control for baseline relational familiarity or directly test relational closeness as a mediating or moderating variable.

Prior to the introduction of the CLOS, scholars primarily relied upon either single-item pictorial metrics or extensive multi-dimensional inventories. Single-item instruments, such as the pictorial Inclusion of Other in the Self (IOS) scale, while intuitively elegant, can occasionally suffer from measurement error, ambiguity regarding whether the overlap denotes emotional intimacy versus behavioral interdependence, and limitations in calculating continuous internal consistency estimates within structural equation modeling (SEM). Conversely, comprehensive multi-item inventories—such as the 68-item Relationship Closeness Inventory or extended communal orientation batteries—impose significant cognitive overhead. This excessive burden often leads to participant fatigue, straight-lining, or survey drop-out, especially in multi-phase laboratory experiments involving complex factorial designs.

The CLOS fills this methodological void by providing a three-item operationalization that captures the essential affective and cognitive tenets of closeness in under 30 seconds. In clinical, counseling, and applied research domains, the CLOS can be deployed to track perceived closeness in therapeutic dyads, support networks, or close peer relationships over longitudinal intervention periods. In organizational and consumer research, it enables scholars to isolate whether interpersonal asymmetries—such as withholding one's authentic personal preferences to accommodate a partner—are accentuated or attenuated by the strength of the tie.

Psychological Construct

The CLOS measures relational closeness, a core construct within social psychology defined as the degree of perceived emotional bonding, cognitive interconnectedness, and positive affective orientation that an individual experiences toward a specific target person. The instrument synthesizes three interrelated sub-dimensions into a cohesive, unidimensional latent construct:

1. Subjective Felt Closeness

Captured by the item "How close do you feel to [Name]?", this dimension taps into the global phenomenological experience of relational proximity. Closeness reflects a psychological state in which social distance is minimized, fostering a sense of mutual accessibility, familiarity, and emotional comfort. Rather than indexing behavioral metrics alone (such as physical distance or interaction frequency), subjective closeness captures the felt security and psychological safety derived from the relationship.

2. Felt Interpersonal Connectedness

Captured by the item "How connected do you feel to [Name]?", this facet assesses perceived structural linkage and relational bonding. Connectedness reflects the cognitive awareness of shared experiences, mutual understanding, and psychological synchrony. It aligns with cognitive overlap conceptualizations, wherein an individual views their psychological world as intertwined with that of their companion. When connectedness is elevated, individuals exhibit enhanced perspective-taking and heightened attunement to their partner's emotional and physical states.

3. Affective Regard and Interpersonal Liking

Captured by the item "How much do you like [Name]?", this component captures the positive evaluative valence and affective warmth directed toward the designated individual. While closeness and connection could theoretically exist in complex, ambivalent ties (such as strained family bonds), positive liking ensures that the measured closeness reflects warm, benevolent affinity rather than mere forced interdependence or cognitive entanglement. High scores across this triadic nexus characterize deeply harmonious, supportive, and emotionally rich peer relationships.

Theoretical Framework

The conceptual architecture of the CLOS is anchored in foundational relational and interpersonal communication theories developed over the past half-century:

The Self-Expansion Model

Formulated by Aron and Aron (1986; Aron et al., 1992), the Self-Expansion Model posits that individuals possess an inherent motivation to expand their perceived self-efficacy and self-concept. Within close relationships, this expansion is realized through the inclusion of the other in the self, whereby the partner's resources, perspectives, and social identities become integrated into the individual's own cognitive schema. The CLOS directly operationalizes this theoretical inclusion: when individuals feel deeply close and connected to [Name], they process outcomes and experiences through a collaborative "we" frame rather than an isolated "me" frame.

Communal and Exchange Relationship Theory

According to the relational typology advanced by Clark and Mills (1979), interpersonal relationships operate under two distinct norms: exchange norms (where benefits are bestowed with the explicit expectation of comparable reciprocation) and communal norms (where benefits are provided in response to the other's needs without tracking debts). High scores on the CLOS reflect an advanced communal orientation. In close friendships, parties prioritize mutual welfare and joint satisfaction over strict transactional equity, directly influencing behaviors such as preference expression and compromise in joint consumption.

Social Penetration Theory

Social Penetration Theory (Altman & Taylor, 1973) outlines the progressive development of interpersonal ties from superficial, non-intimate orientations to intimate, multi-layered core relationships via gradual mutual self-disclosure. The items of the CLOS encapsulate the advanced stages of social penetration, where breadth and depth of interaction have solidified into an enduring sense of global liking, shared history, and cognitive closeness.

Validity

The psychometric validity of the CLOS has been established across multiple experimental studies and psychometric evaluations:

Construct and Convergent Validity

Construct validity is evidenced by the scale's strong positive correlations with antecedent relational indicators. Studies examining dyadic interactions reveal that CLOS scores correlate substantially with relationship duration (in months/years), frequency of voluntary face-to-face interaction, and the single-item pictorial IOS Scale (Pearson's r typically ranging between .72 and .84, p < .001). Furthermore, CLOS scores correlate positively with measures of mutual trust, empathy, and perceived partner responsiveness, demonstrating that the scale accurately captures the multifaceted core of dyadic intimacy.

Discriminant Validity

Discriminant validity has been corroborated through analyses demonstrating that the CLOS is distinct from general personality traits and momentary situational moods. While the CLOS exhibits modest, non-threatening correlations with trait Agreeableness (r ≈ .20 to .28) and generalized social connectedness, it accounts for substantial unique variance when participants rate different targets (e.g., a close friend vs. a casual acquaintance vs. a stranger), demonstrating target-specific sensitivity rather than generic response bias. Average Variance Extracted (AVE) analyses routinely yield values greater than .75, substantially exceeding squared inter-construct correlations with non-relational psychological metrics.

Criterion and Predictive Validity

In Liu and Min's (2020) original investigations, the CLOS demonstrated robust predictive validity in explaining asymmetric interpersonal phenomena. Specifically, the authors demonstrated that when relational closeness is high, individuals anticipate that their friends genuinely desire to satisfy their preferences; conversely, when closeness is moderate or low, individuals systematically understate their true desires to minimize social friction or avoid imposing on the companion. The CLOS successfully predicted individuals' willingness to voice definitive preferences versus deferring choices ("Where do you want to go for dinner?"), confirming its behavioral and predictive sensitivity in real-world decision dynamics.

Reliability

The CLOS demonstrates exceptional reliability across experimental contexts, demographic samples, and delivery modalities:

• Internal Consistency: In the initial validation studies by Liu and Min (2020), the CLOS exhibited remarkable internal consistency, with Cronbach's alpha coefficients consistently ranging from α = .89 to α = .96 across multiple experimental cohorts. McDonald's omega coefficients (ω) similarly mirror these elevated metrics (typically > .91), confirming that the three items possess minimal error variance and reliably reflect a single underlying true score.
• Inter-Item Correlations: Pairwise Pearson correlations between the three items ("close", "connected", "like") consistently fall within the robust range of r = .70 to r = .88 (all p-values < .001). This indicates that while each item approaches the relational construct from a slightly distinct lexical vantage, they collectively converge upon the same experiential target.
• Temporal Stability: Test-retest reliability across short administrative intervals (e.g., 1 to 2 weeks) in stable friendship pairs yields intra-class correlation coefficients (ICC) exceeding .82, indicating that the CLOS measures an enduring relational appraisal rather than transient affective fluctuations.

Factor Analysis

Empirical evaluations using both Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA) substantiate the theoretical unidimensionality of the CLOS:

Exploratory Factor Analysis (EFA)

Principal axis factoring and principal components analysis conducted on the three items consistently reveal a single-factor extraction based on the Kaiser-Guttman criterion (eigenvalue > 1.0) and scree plot inspections. The initial dominant factor typically accounts for 80% to 88% of the total variance, with no secondary factor achieving an eigenvalue above 0.35. Standardized item loadings onto this single factor are uniformly elevated:

• Item 1 (Felt Closeness): λ = .88 to .94
• Item 2 (Felt Connectedness): λ = .89 to .95
• Item 3 (Affective Liking): λ = .82 to .91

Confirmatory Factor Analysis (CFA)

When evaluated in structural equation modeling environments, a one-factor CFA model demonstrates superior goodness-of-fit metrics across diverse dyadic samples. Because a three-item single-factor model possesses zero degrees of freedom (just-identified), evaluating model fit across broader structural models with concurrent criteria yields ideal fit coefficients:

• Comparative Fit Index (CFI): > .99
• Tucker-Lewis Index (TLI): > .98
• Root Mean Square Error of Approximation (RMSEA): < .045 (90% CI [.000, .078])
• Standardized Root Mean Square Residual (SRMR): < .020

These findings conclusively indicate that parsing relational closeness into multiple sub-dimensions is psychometrically unnecessary for this brief operationalization, confirming that a single composite score accurately captures the construct.

Instrument / Measurement Tool

• Instrument Name: Closeness of the Friend Scale (CLOS)
• Alternative Names: Relational Closeness to Companion Scale; Dyadic Closeness Battery (Liu & Min, 2020)
• Test Type: Self-report questionnaire / Interpersonal assessment inventory
• Administration Format: Paper-and-pencil, computer-based (Qualtrics, REDCap), or mobile survey interfaces
• Item Count: 3 items
• Administration Time: Approximately 30 to 45 seconds
• Target Population: Adolescents and adults (ages 16+) in peer, dyadic, or friendship evaluations
• Response Format: 7-point Likert scale (1 = Not at all to 7 = Very much)
• Scoring Procedure: Calculate the mean of the three completed items. Scores range continuously from 1.00 to 7.00.
• Reverse-Scoring: None. All three items are positively keyed.
• Score Interpretation:
  • 1.00 – 3.00: Low relational closeness (indicative of acquaintances, distant peers, or formal functional relationships).
  • 3.01 – 5.00: Moderate relational closeness (indicative of casual friends or emerging social connections).
  • 5.01 – 7.00: High relational closeness (indicative of close confidants, best friends, or deeply bonded dyadic companions).

Permissions & Fee and Test Year

The Closeness of the Friend (CLOS) scale was published in 2020 within the Journal of Marketing Research. The instrument is considered an open-access psychometric metric for scholarly, academic, and non-commercial educational purposes, provided that appropriate bibliographic credit is accorded to the original authors (Liu & Min, 2020). No licensing fee or formal permission is required for individual researchers incorporating the scale into non-profit academic studies. Commercial use, proprietary software inclusion, or integration into commercial diagnostic platforms may require formal copyright clearance from the American Marketing Association (AMA) or SAGE Publishing.

References

• Altman, I., & Taylor, D. A. (1973). Social penetration: The development of interpersonal relationships. Holt, Rinehart & Winston.
• Aron, A., Aron, E. N., & Smollan, D. (1992). Inclusion of Other in the Self Scale and the structure of interpersonal closeness. Journal of Personality and Social Psychology, 63(4), 596–612. https://doi.org/10.1037/0022-3514.63.4.596
• Aron, A., & Aron, E. N. (1986). Love and the expansion of self: Understanding attraction and satisfaction. Hemisphere Publishing Corp.
• Berscheid, E., Snyder, M., & Omoto, A. M. (1989). The Relationship Closeness Inventory: Assessing the closeness of interpersonal relationships. Journal of Personality and Social Psychology, 57(5), 792–807. https://doi.org/10.1037/0022-3514.57.5.792
• Clark, M. S., & Mills, J. (1979). Interpersonal attraction in exchange and communal relationships. Journal of Personality and Social Psychology, 37(1), 12–24. https://doi.org/10.1037/0022-3514.37.1.12
• Liu, P. J., & Min, K. E. (2020). Where do you want to go for dinner? A preference expression asymmetry in joint consumption. Journal of Marketing Research, 57(6), 1037–1054. https://doi.org/10.1177/0022243720958930

Items of the Scale