{smcl} {* *! version 1.0.1 07oct2026}{...} {vieweralsosee "mispauto" "help mispauto"}{...} {vieweralsosee "mispauto thursby" "help mispauto_thursby"}{...} {vieweralsosee "mispauto godfrey" "help mispauto_godfrey"}{...} {vieweralsosee "mispauto ghutton" "help mispauto_ghutton"}{...} {vieweralsosee "mispauto knottnerus" "help mispauto_knottnerus"}{...} {viewerjumpto "The map" "mispauto_methods##map"}{...} {viewerjumpto "Thursby (1981)" "mispauto_methods##thursby"}{...} {viewerjumpto "Knottnerus (1985)" "mispauto_methods##knott"}{...} {viewerjumpto "Godfrey (1987)" "mispauto_methods##godfrey"}{...} {viewerjumpto "Godfrey and Hutton (1994)" "mispauto_methods##gh"}{...} {viewerjumpto "Supporting algorithms" "mispauto_methods##support"}{...} {viewerjumpto "Equivalences verified" "mispauto_methods##equiv"}{...} {viewerjumpto "Decisions the papers leave open" "mispauto_methods##decisions"}{...} {viewerjumpto "Limitations" "mispauto_methods##limits"}{...} {viewerjumpto "References" "mispauto_methods##refs"}{...} {title:Title} {phang} {bf:mispauto methods} {hline 2} Derivations, and the map from each step of the code to the equation it implements {marker map}{...} {title:How to read this page} {pstd} Every computation {cmd:mispauto} performs is listed below against the numbered equation, lemma or algorithm step of the source paper that defines it. Where a cheaper but algebraically equivalent form is used, the equivalence is stated and, where possible, verified numerically against a Stata built-in. Where a paper leaves a choice open, the choice made and the reason are recorded under {help mispauto_methods##decisions:Decisions}. {pstd} Throughout, the maintained model is {p 12 12 2} {cmd:(1) y(t) = x(t)'b + e(t), t = 1, ..., T} {pstd} with {cmd:k} regressors and an intercept. {marker thursby}{...} {title:Thursby (1981): DW, RESET and LRS} {pstd} {bf:Step T1 -- the Durbin{c 150}Watson statistic on (1).} {cmd:d = sum (e(t)-e(t-1))^2 / sum e(t)^2} computed from the OLS residuals of (1). Thursby runs it at a nominal level and reads a significant value as "nonrandom disturbances or misspecification". The p-value is obtained exactly; see {help mispauto_methods##support:Supporting algorithms}. {pstd} {bf:Step T2 -- RESET on (1).} An F test of {cmd:theta = 0} in the augmented regression of Thursby's section II.A, {p 12 12 2} {cmd:y(t) = x(t)'b + z(t)'theta + e(t)} {pstd} where {cmd:z(t)} holds the squares, cubes and fourth powers of the explanatory variables. Thursby adopts this set on the authority of Thursby and Schmidt (1977), whose section 4 compares it with three others; it is {cmd:resetvars(pox)} here and is the default. Thursby notes that a degrees-of-freedom problem can arise when {cmd:k} is large and that {cmd:z} should then be reduced to squares and cubes, or to squares alone; the command does this automatically and reports the set used. {pstd} {bf:Step T3 -- the unrestricted transformed equation, Thursby's (2).} Substituting {cmd:e(t) = rho*e(t-1) + u(t)} into (1) and relaxing the implied restrictions gives {p 8 12 2} {cmd:(2) y(t) = b0 + sum b(i) x(i,t) + sum b(k+i) x(i,t-1) + b(2k+1) y(t-1) + u(t)} {pstd} estimated by OLS. The AR(1) hypothesis is the set of {cmd:k} nonlinear restrictions {p 8 12 2} {cmd:(3) b(i)*b(2k+1) + b(k+i) = 0, i = 1, ..., k} {pstd} {bf:Step T4 -- Durbin's S-test on (2).} Thursby's section II.B step 1 regresses the residuals of (2) on {cmd:u(t-1)} {it:and the right-hand-side variables of (2)}, and tests the significance of the coefficient on {cmd:u(t-1)}. That is exactly what {helpb regress postestimation time series##durbinalt:estat durbinalt} computes at {cmd:lags(1)}, so the built-in is called rather than reimplemented. A significant value rejects the null immediately. {pstd} {bf:Step T5 -- the restricted fit.} Thursby's step 3 writes the restricted estimation explicitly as Durbin's procedure: with {cmd:b(2k+1)} taken from (2), regress {p 12 12 2} {cmd:y(t) - b(2k+1) y(t-1) on x(i,t) - b(2k+1) x(i,t-1)} {pstd} and take the residual sum of squares. Thursby reports that it made almost no difference whether Cochrane{c 150}Orcutt or Durbin's procedure was used; {opt rtemethod()} exposes both, with Durbin's as the default because it is the one the paper writes down. {pstd} {bf:Step T6 -- the likelihood ratio, Thursby's (4).} {p 12 12 2} {cmd:LR = -T * ln( S2u / S2r )} {pstd} asymptotically chi-squared with {cmd:k} degrees of freedom, where {cmd:S2u} is the residual sum of squares from (2) and {cmd:S2r} that from step T5. Because {cmd:S2r >= S2u}, the statistic is non-negative. {pstd} {bf:Step T7 -- the level allocation, Thursby's (6) and (8).} For an overall level {cmd:a} across the three procedures, {p 12 12 2} {cmd:(8) a* = 1 - (1-a)^(1/3)} {pstd} and within the two tests of the LRS procedure the relation {cmd:(1-a**)a** + a** = a*} of his (6), solved in closed form as {p 12 12 2} {cmd:(6) a** = 1 - sqrt(1 - a*)} {pstd} Both rest on the independence of the component tests, which Thursby's section III establishes by Monte Carlo rather than analytically. {pstd} {bf:Step T8 -- the decision rule.} LRS is significant if the S-test is significant, or if the S-test is insignificant and the LR is significant. With D, R and L denoting insignificant and D', R', L' significant outcomes, the eight combinations of Thursby's table on page 118 reduce to: R' implies MS; otherwise L' implies NAR; otherwise D' implies AR(1); otherwise NP. {marker knott}{...} {title:Knottnerus (1985): the blind spots} {pstd} {bf:Step K1 -- equation (12).} Knottnerus's section III proves that, for the probability limits of the OLS estimators of (2), {p 12 12 2} {cmd:plim( b(2k+1)*b(i) + b(k+i) ) = 0} {pstd} for {it:any} stationary error process, not only an AR(1) one. The restrictions (3) that Thursby's LR stage tests are therefore satisfied whatever the errors do, and the asymptotic power of that stage equals its nominal size. The command reports the sample value of {cmd:b3*b1 + b2} with the standard error from {helpb nlcom}, and warns whenever it is indistinguishable from zero. The LR stage is still computed, because the package implements Thursby (1981) as published and because Thursby's reply notes it can be sensitive to non-AR(1) processes in small samples; {opt slrs} drops it. {pstd} {bf:Step K2 -- equation (15).} Knottnerus shows {p 12 12 2} {cmd:plim T^-1 sum u(t) u(t-1) = g1 * ( g2 - g1^2 )} {pstd} where {cmd:g(s)} is the autocorrelation of the disturbances at lag {cmd:s}. Two consequences follow and both are reported: {phang2} (i) if {cmd:g1 = 0} the expression vanishes, so Durbin's S-test is insignificant; and because {cmd:plim d = 2} as well, so is Durbin{c 150}Watson. Thursby's strategy then returns {bf:NP} however strongly the errors are autocorrelated. Knottnerus's footnote 1 names pure seasonal autocorrelation as the leading case. {phang2} (ii) if {cmd:g2 = g1^2} with {cmd:g1} non-zero, the S-test is insignificant while Durbin{c 150}Watson is significant, so genuinely non-AR(1) errors are labelled {bf:AR(1)}. {pstd} {bf:Step K3 -- equation (8).} For an AR(2) error process Knottnerus derives the correlation between consecutive residuals of (2), {p 12 12 2} {cmd:R = -rho1*rho2 / (1 - rho2)} {pstd} and notes from his footnote 2 that {cmd:g1 = rho1/(1-rho2)} and {cmd:g2 = rho2 + rho1*g1}. The command fits an AR(2) to the residuals and reports all four quantities, which is how his non-monotonic power argument can be checked on real data. {pstd} {bf:Step K4 -- the seasonal check.} An F test of the joint significance of lags {cmd:s}, {cmd:2s} and {cmd:3s} in a regression of the residual on those lags alone, where {cmd:s} is the period detected from {helpb tsset}. This is not in Knottnerus; it is the operational form of the case he identified, and it is labelled as Godfrey's remedy rather than as his result. {marker godfrey}{...} {title:Godfrey (1987): the ordered sequence} {pstd} The four hypotheses of his section III, from least to most restrictive: {bf:(a)} regression function misspecified and errors ARMA of unknown order; {bf:(b)} regression function correct, errors ARMA of unknown order; {bf:(c)} regression function correct, errors AR(1); {bf:(d)} regression function correct, errors independent. Testing proceeds along the sequence and stops at the first rejection; the last hypothesis not rejected is adopted. The overall level is at most the sum of the three component levels, which is why the default allocation is Bonferroni. {pstd} {bf:Step G1 -- testing (b), equations (7) to (10).} With {cmd:W = (X, Z)} and {cmd:theta = (b', alpha')'}, his (9) gives {p 12 12 2} {cmd:V(theta) = (W'W)^-1 (W'Omega W) (W'W)^-1} {pstd} and his (10) is the Wald statistic {p 8 12 2} {cmd:(10) (R theta)' [ R (W'W)^-1 (W' Sigma_j W) (W'W)^-1 R' ]^-1 (R theta)} {pstd} compared with chi-squared on {cmd:m} degrees of freedom, where {cmd:R = (0, I_m)} and {cmd:Sigma_j} is the White and Domowitz (1984) estimator whose {cmd:(t,s)} element is {cmd:e(t)e(s)} when {cmd:|t-s| <= j} and zero otherwise. The middle matrix is formed as {p 12 12 2} {cmd:W'Sigma_j W = G(0) + sum_{tau=1}^{j} ( G(tau) + G(tau)' )} {p 12 12 2} {cmd:G(tau) = sum_t e(t) e(t-tau) W(t) W(t-tau)'} {pstd} which is the same matrix in {cmd:O(j T k^2)} rather than {cmd:O(T^2 k^2)} operations. {pstd} {bf:Step G2 -- testing (c), equations (11) and (18).} The alternative is the AR(1+q) scheme of his (11). His argument that the estimators of the {cmd:delta} obtained with {cmd:beta} fixed at {cmd:b} have the same asymptotic distribution as the full maximum likelihood estimators licenses the simple auxiliary regression (18), {p 8 12 2} {cmd:(18) e(t) = d(1) e(t-1) + ... + d(1+q) e(t-1-q) + a(t)} {pstd} run on the OLS residuals of (1), with an F test of {cmd:d(2) = ... = d(1+q) = 0}. The AR(p) generalisation replaces {cmd:1} by {cmd:p} throughout and tests the last {cmd:q} coefficients. Godfrey (1981) shows the same test is appropriate against ARMA(p,q). {pstd} {bf:Equation (18) deliberately excludes the regressors.} Breusch{c 150}Godfrey and {cmd:estat durbinalt} both include them; Godfrey's derivation does not, because {cmd:beta} is held at {cmd:b}. The command follows the paper. This is the single place where {cmd:mispauto} and the familiar Stata built-ins compute different auxiliary regressions on purpose. {pstd} {bf:Step G3 -- testing (d), section III.} A t test of {cmd:rho = 0} in {cmd:e(t) = rho e(t-1) + a(t)} on the OLS residuals, or the Durbin{c 150}Watson statistic. Godfrey notes that Knottnerus's criticism of Durbin{c 150}Watson does not apply here, because in this sequence it is used only to test (d) against (c) and only after (c) has been accepted. {pstd} {bf:Step G4 -- section IV, lagged dependent variables.} When the regressors include lags of {cmd:y}, the White and Domowitz results are unavailable and Godfrey imposes an AR(1+q) or ARMA(1,q) error model and tests by likelihood ratio. {opt lagdep} implements this: {helpb arima} fits the augmented and restricted models, {helpb lrtest} tests (b) and then (c), and (d) is tested by Durbin's h. The command requires {cmd:L.}{it:depvar} to be among the regressors and refuses otherwise. {marker gh}{...} {title:Godfrey and Hutton (1994): errors in variables and simultaneity} {pstd} {bf:Step H1 -- stage 1, equation (13).} With {cmd:e} the IV residual vector and {cmd:Z} the full instrument matrix, {p 12 12 2} {cmd:(13) J = n * R2u ~ chi2(p - k)} {pstd} where {cmd:R2u} is the possibly uncentred R-squared from the OLS regression of {cmd:e} on {cmd:Z}. They note {cmd:J = 0} identically when {cmd:p = k}, so the command refuses an exactly identified equation with a message saying how many further instruments are needed. The statistic is obtained from {helpb ivregress postestimation##overid:estat overid}; the equivalence is verified below. {pstd} {bf:Step H2 -- stage 2, equations (10) and (11).} Hausman's test of {cmd:Omega = 0}, either as the estimator contrast of their (10) or as the variable-addition regression of their (11). {opt hausman(contrast)}, the default, calls the built-in {helpb hausman} on stored OLS and IV fits; {opt hausman(augmented)} uses {helpb ivregress postestimation##endogenous:estat endogenous}. The built-in is called rather than reimplemented because the generalized inverse used when {cmd:V(b)-V(B)} is not positive definite is pivot-order dependent, and Stata's degrees-of-freedom convention would not otherwise be reproduced. {pstd} {bf:Step H3 -- the overall level, section 2.} They prove that {cmd:J} and {cmd:H} are asymptotically independent under the stage-2 null, by showing that the covariance matrix between {cmd:Z'P(X)u} and {cmd:X'u} vanishes because {cmd:X} satisfies the normal equations and {cmd:Z} contains {cmd:Z1}. Hence {p 12 12 2} {cmd:overall level = 1 - (1 - pJ)(1 - pH)} {pstd} {bf:Step H4 -- the decision.} A significant {cmd:J} means IV estimates are of little value and the specification or the instruments must be reconsidered. An insignificant {cmd:J} with a significant {cmd:H} supports presenting IV; an insignificant {cmd:H} supports presenting OLS. Their section 2 explains why a joint test, or separate tests after OLS estimation of their (17), would not serve the purpose: under the stage-1 null with {cmd:Omega} non-zero those OLS estimators are inconsistent and the restrictions would be rejected with probability tending to one. {marker support}{...} {title:Supporting algorithms implemented, not merely cited} {pstd} {bf:Exact Durbin{c 150}Watson p-values: Imhof (1961).} Stata returns only the statistic. Writing {cmd:d = e'Ae/e'e} with {cmd:e = My}, under the null {p 12 12 2} {cmd:P(d <= d0) = P( sum (lam(i) - d0) * chi2_1(i) <= 0 )} {pstd} where the {cmd:lam(i)} are the eigenvalues of {cmd:Q'AQ} and {cmd:Q} is an orthonormal basis of the range of {cmd:M}, obtained as the eigenvectors of the idempotent {cmd:M} with unit eigenvalue. Imhof's (3.2) is then inverted numerically: {p 8 12 2} {cmd:F(0) = 1/2 - (1/pi) * integral_0^inf sin(th(u)) / (u*rh(u)) du} {p 8 12 2} {cmd:th(u) = 0.5 * sum atan(h(i) u), rh(u) = prod (1 + h(i)^2 u^2)^(1/4)} {pstd} Two details follow Imhof's own numerical advice rather than convention. First, the upper limit is {it:computed}, not searched for, from his truncation bound: with all multiplicities one and {cmd:m} terms, {cmd:kk = m/2} and the tail is bounded by {cmd:1/(pi*kk*U^kk*prod|h(i)|^(1/2))}, which is solved for {cmd:U}. Second, the quadrature uses the {bf:trapezoidal} rule, not Simpson's: Imhof reports that "to achieve a given accuracy, longer steps are permissible with the trapezoidal rule than with Simpson's rule", and that accuracy degrades as the degree of the approximating polynomial rises; his Table 1 is computed with the trapezoid alone. The step is halved until two consecutive results agree, as he describes. The route needs a {cmd:T} by {cmd:T} eigendecomposition and is capped by {opt maxtdw()}, above which the large-sample p-value is used and a note is printed. {pstd} {bf:Choosing the truncation lag: White and Domowitz (1984), section 4.} Godfrey refers to their selection procedure without reproducing it. Their equation (4.2) regresses, for each lag, {p 12 12 2} {cmd:e(t) e(t-tau) on psi(tau,t)} {pstd} where {cmd:psi(tau,t)} holds the distinct elements of the outer product {cmd:x(t) x(t-tau)'} -- for a linear regression function the gradient is {cmd:x(t)} -- and their Theorem 4.2 gives {cmd:(n-tau)*R2_0}, with {cmd:R2_0} the {it:constant-unadjusted} R-squared, as asymptotically chi-squared. They offer two rules: a joint test summing the statistics, which is valid because they are asymptotically independent, and a sequential rule with Bonferroni bounds because tests at adjacent lags are dependent. {cmd:truncate(auto)} implements the sequential rule and reports the joint statistic alongside. Their Theorem 3.5 requires {cmd:l = o(T^(1/3))}, which caps the search. {pstd} {bf:Durbin's h: Durbin (1970), equation (11).} {p 12 12 2} {cmd:K2 = n * alpha^2 / ( 1 - n * V(b1) )} {pstd} where {cmd:alpha} is the coefficient from regressing the OLS residual on its own lag without a constant and {cmd:V(b1)} is the least-squares variance estimate of the coefficient on {cmd:y(t-1)} specifically. The procedure requires {cmd:n*V(b1) < 1}, and the command reports a missing value and says why when it is not. {marker equiv}{...} {title:Equivalences, verified numerically} {pstd} {bf:1. Rescaling the regressors before taking powers changes nothing.} {cmd:resetvars(pox)} maps each regressor to the unit interval before forming powers, as {helpb regress postestimation##ovtest:estat ovtest, rhs} does. With the constant and {cmd:x} already in the regression, {p 12 12 2} {cmd:span{ (a+bx)^2, (a+bx)^3, (a+bx)^4 } + span{ 1, x } = span{ x^2, x^3, x^4 } + span{ 1, x }} {pstd} so the joint F statistic is numerically identical. The rescaling exists only to condition the design matrix, which matters once fourth powers of a trended series are involved. The command nonetheless builds the test variables itself rather than calling {cmd:estat ovtest, rhs}, because that command refuses any model containing time-series operators and silently drops indicator variables, neither of which is acceptable inside a strategy that must also run on (2). {pstd} {bf:2. The {cmd:Sigma_j} engine at {cmd:j = 0} is White's estimator.} Setting {cmd:j = 0} leaves {cmd:G(0)} alone, which is the heteroskedasticity-consistent sandwich. Checked against {cmd:regress y x z*, vce(robust)} followed by {cmd:testparm z*}: on a test sample the built-in returned 7.506473 and {cmd:mispauto} 7.698946, a ratio of 1.025641, which is exactly {cmd:n/(n-k) = 200/195}. The difference is Stata's finite-sample adjustment. Godfrey's (10) is written asymptotically with no such adjustment, so the unadjusted form is the faithful one, and that is what the command reports. {pstd} {bf:3. Stata's Sargan statistic is Godfrey and Hutton's {cmd:J}.} {cmd:estat overid} after {cmd:ivregress 2sls} computes {cmd:N*(1 - rss/eqnrss)}, which is {cmd:n} times the uncentred R-squared from regressing the IV residual on the full instrument list -- their (13) exactly. The built-in is therefore called rather than reimplemented. It is suppressed under a robust or HAC {cmd:vce()}, and the command fits the equation without one for this purpose. {pstd} {bf:4. Durbin's S-test is {cmd:estat durbinalt} at one lag.} Thursby's description of step 1 of the LRS procedure and the auxiliary regression in {cmd:durbina.ado} are the same regression and the same test. {marker decisions}{...} {title:Decisions the papers leave open} {pstd} Each entry gives the default, the alternative, and the reason. {phang} {bf:1. RESET test variables.} Default {cmd:pox}, powers of the regressors, because that is what Thursby and Schmidt recommend and what Thursby (1981) uses. Ramsey's {cmd:poy} is available; Stata's bare {cmd:estat ovtest} uses it, which is why the two commands can disagree. {phang} {bf:2. Truncation lag.} Default {cmd:truncate(auto)}, the White and Domowitz procedure above. {cmd:truncate(seasonal)} uses the period from {helpb tsset}, which is Godfrey's only published guidance ("use j >= 4 when the observations are quarterly"), falling back to the Newey{c 150}West rule when the frequency is unknown. An explicit integer overrides both. {phang} {bf:3. Kernel.} Default {cmd:truncated}, the uniform weighting that {cmd:Sigma_j} literally specifies. It is not guaranteed positive semi-definite; when it is not, a spectral generalized inverse keeping the positive eigenvalues is used, the rank actually used becomes the degrees of freedom, and a warning is printed. {cmd:kernel(bartlett)} routes to {helpb newey} and is positive semi-definite by construction. The command never switches silently. {phang} {bf:4. The order q.} Default {cmd:s-1} where {cmd:s} is the detected period, giving 3 for quarterly and 11 for monthly data, which are the values Godfrey names. {phang} {bf:5. The LR stage of LRS.} Retained, because the package implements Thursby (1981) as published, with the Knottnerus result printed beside it whenever it rejects. {opt slrs} drops it and runs the S-test at the full level, which Thursby's reply reports costs about two percentage points of power, citing his unpublished 1983 mimeo. That claim cannot be verified here and is attributed rather than asserted. {phang} {bf:6. The restricted fit.} Default Durbin's transform, written out in Thursby's step 3. {cmd:rtemethod(corc)} and {cmd:rtemethod(prais)} use {helpb prais}. {phang} {bf:7. Leading missing lagged residuals.} Zero-filled, following {cmd:estat durbinalt}'s default, so that results reconcile with the built-in. {opt nomiss0} drops them instead. {phang} {bf:8. Side of the Durbin{c 150}Watson test.} Default lower tail, which is what Thursby's positive-autocorrelation designs require and what the {cmd:dL}/{cmd:dU} tables are built for. {cmd:dwside(two)} is available and is the safer choice when misspecification rather than AR(1) is the suspected alternative. {phang} {bf:9. Degrees of freedom for RESET.} The power set is reduced automatically until at least 10 residual degrees of freedom remain, and the set used is reported. Thursby flags the problem without prescribing a rule. {marker limits}{...} {title:Limitations} {pstd} {bf:The robust Wald statistic has a finite-sample size problem when j is large.} This is a property of HAC-based Wald tests generally, not of this implementation. In a Monte Carlo on a correctly specified model with independent errors at T = 200, forcing {cmd:j = 6} produced rejection rates of about 33% for the truncated kernel and about 24% for the Bartlett kernel routed through Stata's own {helpb newey}, against a nominal 5%, while the plain OLS F test held its size at 5.3%. The two kernels failing together, one of them StataCorp's code, locates the problem in the statistic rather than in either implementation. This is precisely why the truncation lag must be chosen from the data: do not set {opt truncate()} generously "to be safe". {pstd} {bf:There is no finite-sample theory for (10) at all}, and Godfrey reports no size or power evidence for his sequence. {pstd} {bf:Thursby's independence assumptions are Monte Carlo results}, established on his 22 designs at T = 30, 60 and 90, not theorems. The level allocations (6) and (8) inherit that status. {pstd} {bf:The asymptotic independence of J and H is proved only under the stage-2 null}, so the overall level of the Godfrey{c 150}Hutton procedure is exact only when {cmd:Omega = 0}. {pstd} {bf:RESET's documented failures are reproduced faithfully, not patched.} See the Remarks section of {helpb mispauto}. {marker refs}{...} {title:References} {pstd} The five primary papers are listed in {helpb mispauto}. The supporting results implemented here are: {phang} Durbin, J. 1970. Testing for serial correlation in least-squares regression when some of the regressors are lagged dependent variables. {it:Econometrica} 38(3): 410{c 150}421. {browse "https://doi.org/10.2307/1909547":doi:10.2307/1909547}. {phang} Godfrey, L. G. 1981. On the invariance of the Lagrange multiplier test with respect to certain changes in the alternative hypothesis. {it:Econometrica} 49(6): 1443{c 150}1455. {browse "https://doi.org/10.2307/1911410":doi:10.2307/1911410}. {phang} Imhof, J. P. 1961. Computing the distribution of quadratic forms in normal variables. {it:Biometrika} 48(3{c 150}4): 419{c 150}426. {browse "https://doi.org/10.1093/biomet/48.3-4.419":doi:10.1093/biomet/48.3-4.419}. {phang} Porter, R. D., and A. K. Kashyap. 1984. Autocorrelation and the sensitivity of RESET. {it:Economics Letters} 14(2{c 150}3): 229{c 150}233. {browse "https://doi.org/10.1016/0165-1765(84)90087-9":doi:10.1016/0165-1765(84)90087-9}. {phang} Ramsey, J. B. 1969. Tests for specification errors in classical linear least-squares regression analysis. {it:Journal of the Royal Statistical Society, Series B} 31(2): 350{c 150}371. {browse "https://doi.org/10.1111/j.2517-6161.1969.tb00796.x":doi:10.1111/j.2517-6161.1969.tb00796.x}. {phang} Thursby, J. G., and P. Schmidt. 1977. Some properties of tests for specification error in a linear regression model. {it:Journal of the American Statistical Association} 72(359): 635{c 150}641. {browse "https://doi.org/10.1080/01621459.1977.10480627":doi:10.1080/01621459.1977.10480627}. {phang} White, H., and I. Domowitz. 1984. Nonlinear regression with dependent observations. {it:Econometrica} 52(1): 143{c 150}161. {browse "https://doi.org/10.2307/1911465":doi:10.2307/1911465}. {pstd} Amemiya (1973), {browse "https://doi.org/10.2307/1914092":doi:10.2307/1914092}, is cited as the estimator Godfrey recommends after AR(1) is rejected, and is not on the estimation path. {title:Author} {pstd} Dr Merwan Roudane{break} {browse "mailto:merwanroudane920@gmail.com":merwanroudane920@gmail.com}{break} {browse "https://github.com/merwanroudane":github.com/merwanroudane}