Diagnose Response Bias and Heterogeneity: A latent class approach on Indian household inflation expectation survey

 

Sunil Kumar

Alliance University, Bangalore, India,

*Corresponding Author’s Email: sunilbhougal06@gmail.com

 

ABSTRACT:

The main aim of this paper is to evaluate properties of the survey based households inflation expectations, conducted by the Reserve Bank of India (RBI). The results of Inflations expectation survey of households (IESH) regarding their expectations on prices for next quarter shows that there is significant heterogeneity in the responses. The heterogeneity is accounting by estimating a latent class model. Five classes of respondents are identified using attitudinal and knowledge questions. Also, latent class analysis has been hailed as a promising technique for studying the measurement errors in the response of the respondents. It is found that the respondents have given the false response to the questions of expectations on prices of non-food products and household durables.

 

KEYWORDS: Inflation Expectation, Latent Class Analysis, Measurement error, classification, Indicators.

JEL:C38; E31.

 

 


1. INTRODUCTION:

In household surveys gathering information on inflation expectations, Barnett et al (2010) found a wide increase in cross sectional dispersion during the recession periods, a study of U.K. It is at odds with standard rational expectations models that are at the essential of most central banks forecasting models. Recent studies has focused on explaining the deviations from full information rational expectations models in frameworks in which some form of limited information or bounded rationality is assumed {see Mankiw and Reis (2002)}.

 

One of the sources of bounded rationality of consumers is biases associated with the mode of responding. Depending on the literature one can find three to four distinctive response styles that affect responding and thus results of a research.

 

Fischer, Zealand, Fontaine, Vijver, and Hemert (2009) point to three response styles namely acquiescence, extreme response style and social desirability. Baumgartner and Steenkamp (2006) add to this list mid-point responding, which is sometimes seen as a mirror image of the extreme response style (Moors, 2003). With respect to economic surveys, acquiescence, which is associated with agreeing to the item content, seems not to be the case, as questions are formulated in a way which does not allow for agreeing. Extreme response style is mostly assessed as tendency to endorse either the most positive or the most negative categories at both sides of the rating scale (Weijters, Geuens, and Schillewaert, 2010), which is also hard to be found in economic surveys as they usually focus on one area of interest (economic environment) and respondents usually have in the area predetermined opinions affecting their own answers or even a pattern of responding associated with whole questionnaire. Midpoint responding for balanced items can be justified by lack of peculiar opinions with respect to the developments of the economy and thus might be present in economic surveys. Social desirability, which is often referred as tendency to responding in a way that presents them favorably according to current cultural norms (Mick, 1996).

 

Nevertheless, the social survey biases have been mostly investigated with social surveys. Therefore, the developed framework needs to be modified in order to detect peculiarities of economic surveys. We hypothesize that in economic surveys the patterns of responding might interact combining social desirability associated with current (or more persistent moods) regarding the state of the economy ad extreme response style associated with adopting a simple negative or positive way of thinking. Due to difficulties associated with questions about the state of the economy and the fact that respondents are very often asked to make forecasts, although they are not specialized in this field, their answers might be based on very simple positive or negative way. Following the results for other developing countries, we might expect that the prevailing bias in economic surveys might be an extreme but only negative response style. 

 

An important fact is that it is not possible to detect any response style with a single item. One of the most promising techniques in analyzing response patterns is statistical modelling (Baumgartner and Steenkamp, 2006) among which the use of latent class models seems to be one of the most promising (Kankaraš, Moors, and Vermunt, 2011; Moors, 2003; M. Morren, Gelissen, and Vermunt, 2012). In this paper we focus on one of the areas present in economic questionnaires namely inflation expectations and without a priori assumptions we check with latent class approach for possible mode of answering in the Indian survey. 

 

According to the RBI’s Inflation expectation survey of household’s questionnaire which comprises a question on future price expectations s i.e. Block 2: Expectations of respondents on prices in next 3 months? The respondents covered in the survey may incorporate extreme (negative) responses to complain against their economic situation or their dissatisfaction with the government. Such behavior results in certain patterns of responding which have already been detected by (Bovi, 2009).So, in this paper we particularly address the issue of identifying negative response style using data from the Inflation expectations survey of households. We select data from a single quarter - the first quarter of 2012 (27th round data). The paper is arranged in the following sections. In section 2, the data of Inflation expectations survey is described. In section 3, we discuss how latent class models may be used to handle the extreme response bias in the Inflation expectations survey. Section 4 discussed the latent class model with all possible indicators, applied to the measurement of extreme response bias. Section 5 concludes with a discussion on results.

 

2. Inflation Expectations Survey of Households - description of the survey and basic statistics

Description of the data

Reserve Bank of India has been conducting Inflation Expectations Survey of Households (IESH) on a quarterly basis, since September 2005. The survey elicits qualitative and quantitative responses for three-month ahead and one-year ahead period on expected price changes and inflation. Inflation expectations of households (HHs) are subjective assessments and are based on their individual consumption baskets and therefore, may be different from the official inflation numbers released periodically by the government. Again, they are rather not assumed to be based on forecasts of any official measure of inflation, though these inflation expectations provide useful inputs on directional movements of future inflation. In the present study, data from the Jan – March, 2012 (27th round), IESH surveys were used in the analysis; a total of 3792 interviews were used, where94.8% is the response rate of 27th round.

 

Sample Coverage and Data collection

The survey is conducted simultaneously in 12 cities that cover adult respondents of 18 years and above. The major metropolitan cities, viz., Delhi, Kolkata, Mumbai and Chennai are represented by 500 households each, while another eight cities, viz., Jaipur, Lucknow, Bhopal, Ahmedabad, Patna, Guwahati, Bengaluru and Hyderabad are represented by 250 households each. The respondents having a view on perceived current inflation are well spread across the cities to provide a good geographical coverage. The survey schedule is organized into seven blocks covering the respondent profile (block 1), general and product-wise price expectations (block 2 and 3), feedback on RBI's action to control inflation (block 4), current and expected inflation rate (block 5), amount paid for the purchase of major food items during last one month (block 6) and the expectations on changes in income/wages (block 7).

 

The response options for price changes are (i) price increase more than current rate, (ii) price increase similar to current rate, (iii) price increase less than current rate, (iv) no change in prices, and (v) decline in prices. The inflation rates are collected in intervals - the lowest being ‘less than 1 per cent’ and the highest being ‘16 per cent and above’ with 100 basis point size for all intermediate classes. Findings of IESH for last three rounds.

 

3. Methodology of Latent Class Analysis

A characteristic feature of the latent class analysis is that the latent variables and items are discrete. The LCA uses the cross sectional data to measure the latent class variable.


Table 1: Percentage of respondent’s product wise expectations of prices for three month.

 

Round no./Survey period (Quarter ended)

 

Mar - 12

Options

Three month ahead (percentage of respondents)

Price will increase

98.2

Price increase more than current rate

75.6

Price increase similar to current rate

15.9

Price increase less than current rate

6.7

No change in prices

1.6

Decline in prices

0.2

 

Table 2: percentage of respondents expecting general price movements in coherence with movements in price expectations of various product groups

Round no.

Survey quarter

Food

Non food

Household durables

Housing

Cost of services

 

Three month ahead

27

Mar-12

87.7

82.7

65.4

84.1

83.7

 


It identifies the classes, their probabilities, relates probabilities to covariates and classifies individuals into classes. The latent class model assumes that there are a finite number of preference classes with homogeneous preferences within each class. These preferences are assumed to vary significantly across classes. Answers to attitudinal questions are used to estimate the unconditional probability that a respondent belongs to class, then the conditional probability that an individual belongs to a certain class can be estimated. The model assumes conditional independence – that is, within a latent class the observed (indicator) variables are independently distributed – although that assumption can be relaxed (eg., Sinclair and Gastwirth, 1996; Vacek, 1985). Almost all the attempts to assess error in survey variables using LCA that we are aware of are based on the assumption of conditional independence (eg. Biemer and Wiesen, 2002; Biemer and Witt, 1996, Sinclair and Gastwirth, 1998).

 

LCA produces unconditional probabilities gk=P(c=k) that represent the probability that the units being classified (in our case, the survey respondents) being to each class of the latent variable. These unconditional probabilities estimate the unconditional probability of a respondent belonging to certain class (or the relative size of each latent class). In addition, LCA models also produce estimates of item (question) response probabilities conditional on class membership.

 

In this article, we will use the set of assumptions proposed by Sinclair and Gastwirth (1996) and by Biemer (2004). We fit the LCA models based on the question on expectations of respondents on prices in next 3 months and next one year in general (D), food products (E), non-food products (F), household durables (G), housing (H) and services (I), with polytomous options of responses (i.e. price increase more than current rate; price increase similar to current rate; price increase less than current rate; no change in prices; decline in prices), based on the questionnaire of Inflation expectations survey of households, by Department of Statistics and Information Management, Reserve Bank of India. Using different grouping variables to achieve identifiable models i.e. gender (B), and the age (C) groups of the respondents are considered here as grouping variables.

 

3.1 Choosing the number of classes

To find the number of latent classes of latent variable, poLCA software package in R statistical computing environment has been used. In IESH survey of RBI, the respondents were asked to provide answers (on the Likert scale) to several expectations on prices in next three months. The response variables were the manifest variables of a latent class model. The basic model considered is with no covariates.

 

Table 3: Parameters on converged latent class models without covariates

Number of

classes

p

LL

AIC

BIC

1

24

-21561.42

43170.83

43320.61

2

49

-16872.17

33842.34

34148.13

3

74

-16626.84

33401.68

33863.49

4

99

-15504.40

31206.8

31824.62

5

124

-15043.78

30335.56

31109.40

6

149

-14942.39

30183.79

31112.64

7

174

-14883.24

30114.48

31200.35

 

Table 3 summarizes the statistics which supports the existence of heterogeneity in the responses of the respondents. It suggests the existence of a number of latent classes. The best fitting model considered based on information criteria i.e. Akaike Information Criteria (AIC) and Bayesian Information Criteria (BIC). The BIC is considered to be more conservative due to its more stringent penalty for the number of additional parameters (Schwartz, 1978).

 

Table 3 depicts the heterogeneity in the data. It suggests the existence of a number of latent classes. The minimum BIC statistics is associated with 5 latent classes suggesting that model with 5 classes is optimal.

 

 


3.2 Characterizing classes and compares the models

The estimated class conditional probabilities were used to characterize the classes. I have highlighted the probabilities greater than 0.70 in the table with bold format, which are used to describe each of the identified classes.

 


 

 

Table 4:Class conditional outcome probabilities

Indicators

Class 1

Class 2

Class 3

Class 4

Class 5

Expectations of respondent on prices in next 3 months

General ( C )

i

0.9899

1

0

0

0

ii

0.0101

0

0

0

1

iii

0

0

0

1

0

iv

0

0

0.8971

0

0

v

0

0

0.1029

0

0

Food Products (D)

i

0.8636

0.8995

0.0441

0.1461

0.0636

ii

0.1006

0.0864

0.1029

0.0824

0.8779

iii

0.0258

0.0128

0.1176

0.7453

0.0499

iv

0.0088

0.0012

0.6324

0.0187

0.0069

v

0.0012

0

0.1029

0.0075

0.0017

Non Food Products ( E )

i

0.6462

0.8891

0.0147

0.0487

0.0418

ii

0.2484

0.0897

0.1324

0.0974

0.8602

iii

0.0809

0.0212

0.1176

0.7865

0.0791

iv

0.0245

0

0.6765

0.0599

0.0189

v

0

0

0.0588

0.0075

0

Household durables (F)

i

0.2493

0.8223

0

0.0037

0.0128

ii

0.286

0.1777

0

0.0524

0.6075

iii

0.2836

0

0.0882

0.5581

0.2442

iv

0.1437

0

0.7353

0.3596

0.1184

v

0.0374

0

0.1765

0.0262

0.0171

Housing (G)

i

0.7196

0.9532

0.0735

0.0974

0.1448

ii

0.1341

0.0468

0.1029

0.2734

0.7715

iii

0.0914

0

0.2353

0.5468

0.0201

iv

0.0467

0

0.4853

0.0787

0.0602

v

0.0082

0

0.1029

0.0037

0.0034

Services (H)

i

0.734

0.9071

0.1029

0.0674

0.091

ii

0.0931

0.0929

0.1176

0.0627

0.8078

iii

0.1087

0

0.0882

0.7041

0.0617

iv

0.0572

0

0.6324

0.161

0.0395

v

0.007

0

0.0588

0.0037

0

 


Class 1

About 19% of respondents were probabilistically assigned to this class. Around 99% of this class respondents stated that in general the price may increase more than the current rate in coming 3 months. About 86% of respondents are in favour that the price increase more than the current rate for food products. About 72% of the respondents expectation that the price increase more than the current rate for housing. Finally, around 73% of respondents expect that for services, the price increase more than the current rate.

 

Class 2

About 57% of respondents were probabilistically assigned to this class. Respondents are in favour of price increase more than the current rate for next 3 months in all the indicator variables, i.e. in general (100%); for food products (Less than 90%); for non-food products (Less than 89%); for household durables (Around 82%); for housing (Around 95%) and for services (less than 91%).

 

Class 3

Only 1.8% of respondents are in favour of no change in prices for the next three months. Around 90% of the respondents are in favour that in general there will be no change in prices for the next quarter. Around 74% of the respondents feels that no change in prices for household durables in the next quarter. But for class three, the heterogeneity level in the respondents is very high for food products, household durables, housing and services.

 

Class 4

Around 7% of the respondents expect that the price increase less than current rate. All feels that in general the price increase less than the current rate. Around 75% of them are in faour that the food products price will increase but with less than current rate for the next quarter. Around 79% respondents of this class expect that the price for non food products increase but with less than the current rate. Finally, about 70% of them are in favour of price increase but with less than current rate for services.

 

Class 5

About 15% of respondents are in favor that the prices will increase with the similar to current rate. All respondents in general are in favor that the price increase similar to current rate. About 88%, 86%, &&% and 81% of respondents of class 5 are in favor of food products, non-food products, household durables, housing and services, respectively.

 

Table 4 illustrates the estimated class conditional response probabilities for the indicators C, D, E, F, G and H with each column corresponding to a latent class of consumer sentiment, and each row corresponding to classes of the indicator variable response.

 

The classification error probabilities for the indicator variable C are for . Examples are when a respondent feels that there will no change in price in next quarter, but respond to ‘C’ by saying that the prices decline in next quarter, i.e. . Some of the response probability of different indicators is as under:

; ; ; ; ; ; ; .

 

From the above, one can interpret the following points:

i)       Some respondents are complaining against the government by giving the responses in terms of response (error) probabilities.

ii)     Respondents have finding difficulties to respond correctly due to certain reasons, i.e. not able to understand the question properly, wording in the statement of the questions is not clear.

 

CONCLUSION:

LCA method have considerable more potential for providing more valid estimates of IESH; however with this method one can clearly identify the classes of the latent variable and also identify the problems in the questionnaire and the wording of questions. In this paper, identified the heterogeneity in the data by defining five latent classes of the latent variable and the problems in the questionnaire are identified in terms of response probabilities which would have been very difficult to discover by using the other analysis. From the analysis, it is found that the respondents have given the false response to the questions E and F i.e. non-food products and household durables, respectively. The analytical technique described in this paper could provide a means for evaluating the error in the new design.

 

REFERENCES:

1.       Barnett, A., Mumtaz, H., Paustian, M. and Pezzini, S. (2010). Household inflation expectations in the U. K.: exploiting the cross sectional dimension. Mimeo, Bank of England, November.

2.       Baumgartner, H. and Jan-Benedict E.M. Steenkamp (2006). Response Biases in Marketing Research, [in:] Rajiv Grover and Marco Vriens (eds.), Handbook of Marketing Research, Thousand Oaks, CA: Sage, pp. 95-109.

3.       Biemer, P. P. (2004). An analysis of classification error for the revised current population survey employment questions. Survey Methodology, 30, 2, 127-140.

4.       Biemer, P. and Witt, M. (1996).Estimation of Measurement Bias in Self-Reports of Drug

5.       Use with Applications to the National Household Survey on Drug Abuse. Journal of Official Statistics, Vol.12, No.3, pp. 275–300.

6.       Biemer, P.P., Wiesen, C. (2002). Measurement error evaluation of self-reported drug use: A latent class analysis of the US National Household Survey on Drug Abuse. Journal of the Royal Statistical Society, Series A: Statistics in Society. 165, (Part 1), 97-119.

7.       Bovi, M. (2009).Economic versus Psychological Forecasting.Evidence from consumer confidence surveys. Journal of Economic Psychology, 30, 4, 563-574.

8.       Fischer, R., Fontaine, J. R. J., van de Vijver, F. J. R.,  and  van Hemert, D. A. (2009). What is style and what is bias in cross-cultural comparisons? An examination of acquiescent response styles in cross-cultural research. In A. Gari and  K. Mylonas (Eds.), Quod erat demonstrandum: From herodotus’ ethnographic journeys to cross-cultural research (pp. 137-148). Athens: Pedio. Retrieved from http://iaccp.org/drupal/sites/default/files/spetses_pdf/16_Fischer.pdf

9.       Kankaras, M., Moors, G., and Vermunt, J.K (2010). Testing for measurement invariance with latent class analysis. In: E. Davidov, P. Schmidt, and J. Billiet (eds.), Cross-Cultural Analysis: Methods and Applications, 359-384. New York: Routledge.

10.     Morren, M., Gelissen, J. P. T. M., Vermunt, J. K.(2011). Dealing with extreme response style in cross cultural research: A restricted latent class factor analysis approach, 41, 1, 13-47.

11.     Morren, M., Gelissen, J. P. T. M., Vermunt, J. K. (2012). The impact of controlling for extreme responding on measurement equivalence in cross-cultural research. Methodology: European Journal of Research Methods for the Behavioral and Social Sciences, Vol 8(4), 2012, 159-170.http://dx.doi.org/10.1027/1614-2241/a000048

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16.     Moors.G. (2003).Diagnosing response style behavior by means of a latent class factor approach. Socio-demographic correlates of gender role attitudes and perceptions of Ethnic discrimination reexamined. Quality  and  Quantity, 37, 277-302.

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18.Weijters, B., Geuens, M. and Schillewaert, N. (2010). The individual consistency of  acquiescence and extreme response style in self report questionnaires. Applied Psychological Measurement, 34, 105-121.

 

 

 

 

 


Block 2: Expectations of respondent on prices in next three months  (please tick (√) the relevant cell for each col.)

Options

General

(D)

Food Products (E)

Non- food products

(F)

Household durables

(G)

Housing

(H)

Services (I)

Price increase more than current rate

 

 

 

 

 

 

Price increase similar to current rate

Price increase less than current rate

No change in prices.

Decline in prices.

 

 

 

 

 

 

 

 

 

 

 

 

 

Source: IESH, conducted by Reserve Bank of India.

 


 

 

 

Received on 19.12.2015       Modified on 24.12.2015

Accepted on 28.12.2015      © A&V Publication all right reserved

Int. J. Ad. Social Sciences 3(4): Oct. - Dec., 2015; Page 152-158