Investment in Independence
Contact: Dorly Deeg
Investment in Independence (IiI) is a measure of the importance of independent living to a person, or the ambition of a person to remain independent. This concept might thus be especially important in relation to outcomes such as functional decline and institutionalization, which affect independence. Although studies show that older people value their independence and consider mobility limitations as a threat to losing their independence (Gabriel & Bowling, 2004), it cannot be assumed that all older people will place the same value in maintaining their independence as all others. However, investment in independence is a much less well-studied personality characteristic than, for example, mastery or self-efficacy. People who attach greater value to their independence may be more likely to exhibit behaviour that, in their belief, will ensure they attain their goal of remaining independent than people who attach less value to their independence.
Measurement instrument in LASA
The Investment in Independence (IiI) scale was derived from the Metamemory in Adulthood (MIA) scale developed by Dixon & Hultsch (1983, 1984, 1988). In the subscale ‘Achievement’ (16 items) ‡, investment in maintaining a good memory is replaced by investment in maintaining independence (Auman et al 2005). Thus, the 16 items quantify how invested older people are in being able to function independently in everyday life.
Unidimensionality of the IiI scale was examined in LASA using the 2005-06 sample (LASA-F). Exploratory factor analyses were carried, to determine the underlying dimensions of the scale, and to identify the subset of questions that corresponds to each of the underlying dimensions (Rooth 2014). The IiI scale consisted of one dimension with 47% explained variance, without the items 4, 5 and 10. The loadings of two questions (items 4 and 5) were low (0.057 and 0.042, respectively), and were excluded. The local dependence of items, which could arise from items with a similar content, was assessed by inspection of the residual correlation matrix. The correlation was high between the items 9 and 10; item 10 was excluded, based on a slightly lower factor loading. Excluding other items did not improve the model.
The descriptive measures of model fit of the 13 remaining items were as follows: Comparative Fit Index 0.910, Tucker Lewis Index 0.892, Root Mean Square Error of Approximation 0.123, Standardized Root Mean Square Residual 0.072 and Cronbach’s alpha 0.87 in 2005-06 and 0.91 in 2008-09. The total score of the 13 items ranged from 13-65, with higher values indicating a higher IiI.
Missing values on the 13 items may be imputed if one or two items of the 13 items were missing. In these cases, mean values on the other items may be used to replace the missing value.
|Loadings (final scale)|
|1.||It is important to me to be able to do things for myself||0.557|
|2.||To take care of myself is something to be proud of||0.575|
|3.||It bothers me when others notice I could not take care of myself||0.419|
|4.a||It would be nice to be able to live independently, but it is not very important||–|
|5.a||It does not bother me when I’m not able to do a task on my own||–|
|6.||I think it is important to work at sustaining my independence||0.727|
|7.||I do my best to improve my ability to function on my own||0.663|
|8.||I admire people who live on their own||0.593|
|9.||My friends often notice my self-sufficiency||0.471|
|10.a||I often notice my friends’ self-sufficiency||–|
|11.||It is important that I am very accurate when remembering appointments||0.704|
|12.||It is important that I am very accurate when taking my medications||0.620|
|13.||It bothers me when I am unable to run errands on my own||0.608|
|14.||I like to do things on my own, without relying on other people to help me||0.796|
|15.||I’m highly motivated to do things on my own||0.868|
|16.||It gives me great satisfaction to be able to accomplish tasks independently||0.879|
a: excluded items
LASAF144 / LASAG144 / LASAH144 /LASAI144 / LASAJ144 (self-administered questionnaire, in Dutch)
LASAF144 / LASAG144 / LASAH144 / LASAI144 / LASAJ144 (J not available yet)
Availability of information per wave ¹
¹ More information about the LASA data collection waves is available here.
* 2B=baseline second cohort;
3B=baseline third cohort;
MB=migrants: baseline first cohort;
J=not available yet;
K=future wave 2021-2022
Sa=data collected in self-administered questionnaire
Previous use in LASA
Cooper et al (2011) showed that there was no evidence of a direct association between baseline investment in independence and 3-year functional decline. Also, there was no evidence of an association between investment in independence and institutionalization. However, in studying the association between baseline physical performance and functional decline, these authors showed evidence that this association was weaker in those with investment in independence scores above the median than in those with investment in independence scores below the median. The authors explained this finding by suggesting a link between investment in independence and factors that influence functional decline including utilization of resources. I.e., people with lower levels of investment in independence are less likely to utilize strategies which prevent decline in the face of challenges to their future independence. However, there was only evidence of interaction when examining the lower cut-points of investment in independence. This suggests that this is not a linear dose–response relationship. It may therefore be not only that having a low level of investment in independence is detrimental, but that having the highest levels of investment is not most beneficial. People with the highest levels of a characteristic such as investment in independence may have more unrealistic expectations of their ability to maintain their independence in older age and therefore be less flexible when faced with challenges to this (Brandtstädter, 2009).
Furthermore, Cooper et al (2011) showed that neither mastery nor self-efficacy – although correlating strongly with one another – correlated with investment in independence (r=0.06). This might be because mastery and self-efficacy refer to experienced control or confidence in one’s ability to take control, whereas investment in independence reflects a personal need for control. People who feel the need to be independent may not actually experience control. This confirms the value in studying these characteristics separately.
- Auman, C., Bosworth, H. B., & Hess, T. M. (2005). Effect of health-related stereotypes on physiological responses of hypertensive middle-aged and older men. The Journals of Gerontology, Series B: Psychological Sciences and Social Sciences, 60, 3–10.
- Brandtstädter, J. (2009). Goal pursuit and goal adjustment: Self-regulation and intentional self-development in changing developmental contexts. Advances in Life Course Research, 14, 52–62.
- Cooper, R., Huisman, M., Kuh, D., Deeg, D.J.H. (2011). Do positive psychological characteristics modify the associations of physical performance with functional decline and institutionalization? Findings from the Longitudinal Aging Study Amsterdam. Journals of Gerontology: Social Sciences, 66(4), 468-477.
- Dixon, R. A., & Hultsch, D. F. (1983). Structure and development of metamemory in adulthood. Journal of Gerontology, 38, 682–688.
- Dixon, R. A., & Hultsch, D. F. (1984). The Metamemory in Adulthood (MIA) instrument. Psychological Documents, 14, 3.
- Dixon, R.A., Hultsch, D.F., Herzog, C. (1988). The Metamemory in Adulthood (MIA) Questionnaire. Psychopharmacology Bulletin 24/4, 671-688).
- Gabriel, Z., & Bowling, A. (2004). Quality of life from the perspectives of older people. Ageing & Society, 24, 675–691.
- Rooth, V. (2014). Association between vision and people’s investment in independence. Thesis VU University Health Sciences, Master Lifestyle and Chronic Disorders, 2014.
‡ A selection of the original MIA-Achievement items is available in LASA-C (1995-96), see documentation Metamemory.
Date of last update: October 29, 2014